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hsmusic-wiki - HSMusic - static wiki software cataloguing collaborative creation
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-rw-r--r--src/data/cacheable-object.js429
-rw-r--r--src/data/checks.js256
-rw-r--r--src/data/composite/control-flow/flipFilter.js36
-rw-r--r--src/data/composite/control-flow/index.js1
-rw-r--r--src/data/composite/control-flow/withAvailabilityFilter.js1
-rw-r--r--src/data/composite/data/index.js1
-rw-r--r--src/data/composite/data/withFilteredList.js16
-rw-r--r--src/data/composite/data/withLengthOfList.js54
-rw-r--r--src/data/composite/data/withMappedList.js20
-rw-r--r--src/data/composite/data/withNearbyItemFromList.js52
-rw-r--r--src/data/composite/data/withPropertyFromList.js22
-rw-r--r--src/data/composite/data/withPropertyFromObject.js38
-rw-r--r--src/data/composite/things/album/index.js1
-rw-r--r--src/data/composite/things/album/withHasCoverArt.js64
-rw-r--r--src/data/composite/things/album/withTracks.js1
-rw-r--r--src/data/composite/things/art-tag/index.js2
-rw-r--r--src/data/composite/things/art-tag/withAllDescendantArtTags.js44
-rw-r--r--src/data/composite/things/art-tag/withAncestorArtTagBaobabTree.js46
-rw-r--r--src/data/composite/things/artist/artistTotalDuration.js25
-rw-r--r--src/data/composite/things/artwork/index.js5
-rw-r--r--src/data/composite/things/artwork/withAttachedArtwork.js43
-rw-r--r--src/data/composite/things/artwork/withContainingArtworkList.js46
-rw-r--r--src/data/composite/things/artwork/withContribsFromAttachedArtwork.js27
-rw-r--r--src/data/composite/things/artwork/withDate.js41
-rw-r--r--src/data/composite/things/artwork/withPropertyFromAttachedArtwork.js65
-rw-r--r--src/data/composite/things/content/contentArtists.js40
-rw-r--r--src/data/composite/things/content/hasAnnotationPart.js25
-rw-r--r--src/data/composite/things/content/helpers/withExpressedOrImplicitArtistReferences.js60
-rw-r--r--src/data/composite/things/content/index.js7
-rw-r--r--src/data/composite/things/content/withAnnotationParts.js93
-rw-r--r--src/data/composite/things/content/withHasAnnotationPart.js43
-rw-r--r--src/data/composite/things/content/withSourceText.js53
-rw-r--r--src/data/composite/things/content/withSourceURLs.js62
-rw-r--r--src/data/composite/things/content/withWebArchiveDate.js41
-rw-r--r--src/data/composite/things/contribution/inheritFromContributionPresets.js2
-rw-r--r--src/data/composite/things/contribution/thingPropertyMatches.js18
-rw-r--r--src/data/composite/things/contribution/thingReferenceTypeMatches.js29
-rw-r--r--src/data/composite/things/contribution/withContainingReverseContributionList.js46
-rw-r--r--src/data/composite/things/contribution/withContributionArtist.js12
-rw-r--r--src/data/composite/things/flash-act/withFlashSide.js6
-rw-r--r--src/data/composite/things/flash/withFlashAct.js6
-rw-r--r--src/data/composite/things/track-section/index.js2
-rw-r--r--src/data/composite/things/track-section/withAlbum.js6
-rw-r--r--src/data/composite/things/track-section/withContinueCountingFrom.js25
-rw-r--r--src/data/composite/things/track-section/withStartCountingFrom.js64
-rw-r--r--src/data/composite/things/track/index.js13
-rw-r--r--src/data/composite/things/track/inheritContributionListFromMainRelease.js (renamed from src/data/composite/things/track/inheritContributionListFromOriginalRelease.js)20
-rw-r--r--src/data/composite/things/track/inheritFromMainRelease.js (renamed from src/data/composite/things/track/inheritFromOriginalRelease.js)18
-rw-r--r--src/data/composite/things/track/trackAdditionalNameList.js38
-rw-r--r--src/data/composite/things/track/trackReverseReferenceList.js38
-rw-r--r--src/data/composite/things/track/withAlbum.js22
-rw-r--r--src/data/composite/things/track/withAllReleases.js46
-rw-r--r--src/data/composite/things/track/withAlwaysReferenceByDirectory.js43
-rw-r--r--src/data/composite/things/track/withContainingTrackSection.js6
-rw-r--r--src/data/composite/things/track/withCoverArtistContribs.js73
-rw-r--r--src/data/composite/things/track/withHasUniqueCoverArt.js76
-rw-r--r--src/data/composite/things/track/withMainRelease.js (renamed from src/data/composite/things/track/withOriginalRelease.js)40
-rw-r--r--src/data/composite/things/track/withOtherReleases.js30
-rw-r--r--src/data/composite/things/track/withPropertyFromAlbum.js18
-rw-r--r--src/data/composite/things/track/withPropertyFromMainRelease.js (renamed from src/data/composite/things/track/withPropertyFromOriginalRelease.js)36
-rw-r--r--src/data/composite/things/track/withTrackArtDate.js24
-rw-r--r--src/data/composite/things/track/withTrackNumber.js50
-rw-r--r--src/data/composite/wiki-data/gobbleSoupyFind.js39
-rw-r--r--src/data/composite/wiki-data/gobbleSoupyReverse.js39
-rw-r--r--src/data/composite/wiki-data/helpers/withResolvedReverse.js40
-rw-r--r--src/data/composite/wiki-data/helpers/withReverseList-template.js193
-rw-r--r--src/data/composite/wiki-data/index.js12
-rw-r--r--src/data/composite/wiki-data/inputSoupyFind.js28
-rw-r--r--src/data/composite/wiki-data/inputSoupyReverse.js32
-rw-r--r--src/data/composite/wiki-data/inputWikiData.js2
-rw-r--r--src/data/composite/wiki-data/splitContentNodesAround.js87
-rw-r--r--src/data/composite/wiki-data/withConstitutedArtwork.js60
-rw-r--r--src/data/composite/wiki-data/withContentNodes.js25
-rw-r--r--src/data/composite/wiki-data/withCoverArtDate.js23
-rw-r--r--src/data/composite/wiki-data/withParsedCommentaryEntries.js261
-rw-r--r--src/data/composite/wiki-data/withRecontextualizedContributionList.js1
-rw-r--r--src/data/composite/wiki-data/withResolvedAnnotatedReferenceList.js33
-rw-r--r--src/data/composite/wiki-data/withResolvedContribs.js3
-rw-r--r--src/data/composite/wiki-data/withResolvedReference.js26
-rw-r--r--src/data/composite/wiki-data/withResolvedReferenceList.js50
-rw-r--r--src/data/composite/wiki-data/withResolvedSeriesList.js131
-rw-r--r--src/data/composite/wiki-data/withReverseAnnotatedReferenceList.js116
-rw-r--r--src/data/composite/wiki-data/withReverseContributionList.js37
-rw-r--r--src/data/composite/wiki-data/withReverseReferenceList.js56
-rw-r--r--src/data/composite/wiki-data/withReverseSingleReferenceList.js50
-rw-r--r--src/data/composite/wiki-data/withUniqueReferencingThing.js41
-rw-r--r--src/data/composite/wiki-properties/additionalFiles.js30
-rw-r--r--src/data/composite/wiki-properties/additionalNameList.js14
-rw-r--r--src/data/composite/wiki-properties/annotatedReferenceList.js14
-rw-r--r--src/data/composite/wiki-properties/commentary.js30
-rw-r--r--src/data/composite/wiki-properties/commentatorArtists.js11
-rw-r--r--src/data/composite/wiki-properties/constitutibleArtwork.js70
-rw-r--r--src/data/composite/wiki-properties/constitutibleArtworkList.js72
-rw-r--r--src/data/composite/wiki-properties/directory.js1
-rw-r--r--src/data/composite/wiki-properties/index.js12
-rw-r--r--src/data/composite/wiki-properties/referenceList.js5
-rw-r--r--src/data/composite/wiki-properties/referencedArtworkList.js37
-rw-r--r--src/data/composite/wiki-properties/reverseAnnotatedReferenceList.js33
-rw-r--r--src/data/composite/wiki-properties/reverseContributionList.js24
-rw-r--r--src/data/composite/wiki-properties/reverseReferenceList.js12
-rw-r--r--src/data/composite/wiki-properties/reverseReferencedArtworkList.js39
-rw-r--r--src/data/composite/wiki-properties/reverseSingleReferenceList.js24
-rw-r--r--src/data/composite/wiki-properties/seriesList.js31
-rw-r--r--src/data/composite/wiki-properties/singleReference.js6
-rw-r--r--src/data/composite/wiki-properties/soupyFind.js14
-rw-r--r--src/data/composite/wiki-properties/soupyReverse.js37
-rw-r--r--src/data/thing.js27
-rw-r--r--src/data/things/additional-file.js47
-rw-r--r--src/data/things/additional-name.js21
-rw-r--r--src/data/things/album.js534
-rw-r--r--src/data/things/art-tag.js131
-rw-r--r--src/data/things/artist.js134
-rw-r--r--src/data/things/artwork.js510
-rw-r--r--src/data/things/content.js205
-rw-r--r--src/data/things/contribution.js89
-rw-r--r--src/data/things/flash.js158
-rw-r--r--src/data/things/group.js163
-rw-r--r--src/data/things/homepage-layout.js314
-rw-r--r--src/data/things/index.js42
-rw-r--r--src/data/things/language.js59
-rw-r--r--src/data/things/sorting-rule.js385
-rw-r--r--src/data/things/static-page.js9
-rw-r--r--src/data/things/track.js483
-rw-r--r--src/data/things/wiki-info.js47
-rw-r--r--src/data/validators.js1104
-rw-r--r--src/data/yaml.js776
126 files changed, 5953 insertions, 3753 deletions
diff --git a/src/data/cacheable-object.js b/src/data/cacheable-object.js
index 010d967a..651a61cf 100644
--- a/src/data/cacheable-object.js
+++ b/src/data/cacheable-object.js
@@ -1,79 +1,3 @@
-// Generally extendable class for caching properties and handling dependencies,
-// with a few key properties:
-//
-// 1) The behavior of every property is defined by its descriptor, which is a
-//    static value stored on the subclass (all instances share the same property
-//    descriptors).
-//
-//  1a) Additional properties may not be added past the time of object
-//      construction, and attempts to do so (including externally setting a
-//      property name which has no corresponding descriptor) will throw a
-//      TypeError. (This is done via an Object.seal(this) call after a newly
-//      created instance defines its own properties according to the descriptor
-//      on its constructor class.)
-//
-// 2) Properties may have two flags set: update and expose. Properties which
-//    update are provided values from the external. Properties which expose
-//    provide values to the external, generally dependent on other update
-//    properties (within the same object).
-//
-//  2a) Properties may be flagged as both updating and exposing. This is so
-//      that the same name may be used for both "output" and "input".
-//
-// 3) Exposed properties have values which are computations dependent on other
-//    properties, as described by a `compute` function on the descriptor.
-//    Depended-upon properties are explicitly listed on the descriptor next to
-//    this function, and are only provided as arguments to the function once
-//    listed.
-//
-//  3a) An exposed property may depend only upon updating properties, not other
-//      exposed properties (within the same object). This is to force the
-//      general complexity of a single object to be fairly simple: inputs
-//      directly determine outputs, with the only in-between step being the
-//      `compute` function, no multiple-layer dependencies. Note that this is
-//      only true within a given object - externally, values provided to one
-//      object's `update` may be (and regularly are) the exposed values of
-//      another object.
-//
-//  3b) If a property both updates and exposes, it is automatically regarded as
-//      a dependancy. (That is, its exposed value will depend on the value it is
-//      updated with.) Rather than a required `compute` function, these have an
-//      optional `transform` function, which takes the update value as its first
-//      argument and then the usual key-value dependencies as its second. If no
-//      `transform` function is provided, the expose value is the same as the
-//      update value.
-//
-// 4) Exposed properties are cached; that is, if no depended-upon properties are
-//    updated, the value of an exposed property is not recomputed.
-//
-//  4a) The cache for an exposed property is invalidated as soon as any of its
-//      dependencies are updated, but the cache itself is lazy: the exposed
-//      value will not be recomputed until it is again accessed. (Likewise, an
-//      exposed value won't be computed for the first time until it is first
-//      accessed.)
-//
-// 5) Updating a property may optionally apply validation checks before passing,
-//    declared by a `validate` function on the `update` block. This function
-//    should either throw an error (e.g. TypeError) or return false if the value
-//    is invalid.
-//
-// 6) Objects do not expect all updating properties to be provided at once.
-//    Incomplete objects are deliberately supported and enabled.
-//
-//  6a) The default value for every updating property is null; undefined is not
-//      accepted as a property value under any circumstances (it always errors).
-//      However, this default may be overridden by specifying a `default` value
-//      on a property's `update` block. (This value will be checked against
-//      the property's validate function.) Note that a property may always be
-//      updated to null, even if the default is non-null. (Null always bypasses
-//      the validate check.)
-//
-//  6b) It's required by the external consumer of an object to determine whether
-//      or not the object is ready for use (within the larger program). This is
-//      convenienced by the static CacheableObject.listAccessibleProperties()
-//      function, which provides a mapping of exposed property names to whether
-//      or not their dependencies are yet met.
-
 import {inspect as nodeInspect} from 'node:util';
 
 import {colors, ENABLE_COLOR} from '#cli';
@@ -84,53 +8,21 @@ function inspect(value) {
 
 export default class CacheableObject {
   static propertyDescriptors = Symbol.for('CacheableObject.propertyDescriptors');
+  static constructorFinalized = Symbol.for('CacheableObject.constructorFinalized');
+  static propertyDependants = Symbol.for('CacheableObject.propertyDependants');
 
-  #propertyUpdateValues = Object.create(null);
-  #propertyUpdateCacheInvalidators = Object.create(null);
-
-  // Note the constructor doesn't take an initial data source. Due to a quirk
-  // of JavaScript, private members can't be accessed before the superclass's
-  // constructor is finished processing - so if we call the overridden
-  // update() function from inside this constructor, it will error when
-  // writing to private members. Pretty bad!
-  //
-  // That means initial data must be provided by following up with update()
-  // after constructing the new instance of the Thing (sub)class.
-
-  constructor() {
-    this.#defineProperties();
-    this.#initializeUpdatingPropertyValues();
-
-    if (CacheableObject.DEBUG_SLOW_TRACK_INVALID_PROPERTIES) {
-      return new Proxy(this, {
-        get: (obj, key) => {
-          if (!Object.hasOwn(obj, key)) {
-            if (key !== 'constructor') {
-              CacheableObject._invalidAccesses.add(`(${obj.constructor.name}).${key}`);
-            }
-          }
-          return obj[key];
-        },
-      });
-    }
-  }
+  static cacheValid = Symbol.for('CacheableObject.cacheValid');
+  static updateValue = Symbol.for('CacheableObject.updateValues');
 
-  #withEachPropertyDescriptor(callback) {
-    const {[CacheableObject.propertyDescriptors]: propertyDescriptors} =
-      this.constructor;
+  constructor({seal = true} = {}) {
+    this[CacheableObject.updateValue] = Object.create(null);
+    this[CacheableObject.cachedValue] = Object.create(null);
+    this[CacheableObject.cacheValid] = Object.create(null);
 
+    const propertyDescriptors = this.constructor[CacheableObject.propertyDescriptors];
     for (const property of Reflect.ownKeys(propertyDescriptors)) {
-      callback(property, propertyDescriptors[property]);
-    }
-  }
-
-  #initializeUpdatingPropertyValues() {
-    this.#withEachPropertyDescriptor((property, descriptor) => {
-      const {flags, update} = descriptor;
-
-      if (!flags.update) {
-        return;
-      }
+      const {flags, update} = propertyDescriptors[property];
+      if (!flags.update) continue;
 
       if (
         typeof update === 'object' &&
@@ -141,188 +33,161 @@ export default class CacheableObject {
       } else {
         this[property] = null;
       }
-    });
+    }
+
+    if (seal) {
+      Object.seal(this);
+    }
   }
 
-  #defineProperties() {
-    if (!this.constructor[CacheableObject.propertyDescriptors]) {
-      throw new Error(`Expected constructor ${this.constructor.name} to provide CacheableObject.propertyDescriptors`);
+  static finalizeCacheableObjectPrototype() {
+    if (Object.hasOwn(this, CacheableObject.constructorFinalized)) {
+      throw new Error(`Constructor ${this.name} already finalized`);
+    }
+
+    if (!this[CacheableObject.propertyDescriptors]) {
+      throw new Error(`Expected constructor ${this.name} to provide CacheableObject.propertyDescriptors`);
     }
 
-    this.#withEachPropertyDescriptor((property, descriptor) => {
-      const {flags} = descriptor;
+    this[CacheableObject.propertyDependants] = Object.create(null);
+
+    const propertyDescriptors = this[CacheableObject.propertyDescriptors];
+    for (const property of Reflect.ownKeys(propertyDescriptors)) {
+      const {flags, update, expose} = propertyDescriptors[property];
 
       const definition = {
         configurable: false,
         enumerable: flags.expose,
       };
 
-      if (flags.update) {
-        definition.set = this.#getUpdateObjectDefinitionSetterFunction(property);
-      }
-
-      if (flags.expose) {
-        definition.get = this.#getExposeObjectDefinitionGetterFunction(property);
-      }
-
-      Object.defineProperty(this, property, definition);
-    });
-
-    Object.seal(this);
-  }
+      if (flags.update) setSetter: {
+        definition.set = function(newValue) {
+          if (newValue === undefined) {
+            throw new TypeError(`Properties cannot be set to undefined`);
+          }
 
-  #getUpdateObjectDefinitionSetterFunction(property) {
-    const {update} = this.#getPropertyDescriptor(property);
-    const validate = update?.validate;
+          const oldValue = this[CacheableObject.updateValue][property];
 
-    return (newValue) => {
-      const oldValue = this.#propertyUpdateValues[property];
+          if (newValue === oldValue) {
+            return;
+          }
 
-      if (newValue === undefined) {
-        throw new TypeError(`Properties cannot be set to undefined`);
-      }
+          if (newValue !== null && update?.validate) {
+            try {
+              const result = update.validate(newValue);
+              if (result === undefined) {
+                throw new TypeError(`Validate function returned undefined`);
+              } else if (result !== true) {
+                throw new TypeError(`Validation failed for value ${newValue}`);
+              }
+            } catch (caughtError) {
+              throw new CacheableObjectPropertyValueError(
+                property, oldValue, newValue, {cause: caughtError});
+            }
+          }
 
-      if (newValue === oldValue) {
-        return;
-      }
+          this[CacheableObject.updateValue][property] = newValue;
 
-      if (newValue !== null && validate) {
-        try {
-          const result = validate(newValue);
-          if (result === undefined) {
-            throw new TypeError(`Validate function returned undefined`);
-          } else if (result !== true) {
-            throw new TypeError(`Validation failed for value ${newValue}`);
+          const dependants = this.constructor[CacheableObject.propertyDependants][property];
+          if (dependants) {
+            for (const dependant of dependants) {
+              this[CacheableObject.cacheValid][dependant] = false;
+            }
           }
-        } catch (caughtError) {
-          throw new CacheableObjectPropertyValueError(
-            property, oldValue, newValue, {cause: caughtError});
-        }
+        };
       }
 
-      this.#propertyUpdateValues[property] = newValue;
-      this.#invalidateCachesDependentUpon(property);
-    };
-  }
-
-  #getPropertyDescriptor(property) {
-    return this.constructor[CacheableObject.propertyDescriptors][property];
-  }
+      if (flags.expose) setGetter: {
+        if (flags.update && !expose?.transform) {
+          definition.get = function() {
+            return this[CacheableObject.updateValue][property];
+          };
 
-  #invalidateCachesDependentUpon(property) {
-    const invalidators = this.#propertyUpdateCacheInvalidators[property];
-    if (!invalidators) {
-      return;
-    }
+          break setGetter;
+        }
 
-    for (const invalidate of invalidators) {
-      invalidate();
-    }
-  }
+        if (flags.update && expose?.compute) {
+          throw new Error(`Updating property ${property} has compute function, should be formatted as transform`);
+        }
 
-  #getExposeObjectDefinitionGetterFunction(property) {
-    const {flags} = this.#getPropertyDescriptor(property);
-    const compute = this.#getExposeComputeFunction(property);
-
-    if (compute) {
-      let cachedValue;
-      const checkCacheValid = this.#getExposeCheckCacheValidFunction(property);
-      return () => {
-        if (checkCacheValid()) {
-          return cachedValue;
-        } else {
-          return (cachedValue = compute());
+        if (!flags.update && !expose?.compute) {
+          throw new Error(`Exposed property ${property} does not update and is missing compute function`);
         }
-      };
-    } else if (!flags.update && !compute) {
-      throw new Error(`Exposed property ${property} does not update and is missing compute function`);
-    } else {
-      return () => this.#propertyUpdateValues[property];
-    }
-  }
 
-  #getExposeComputeFunction(property) {
-    const {flags, expose} = this.#getPropertyDescriptor(property);
+        definition.get = function() {
+          if (this[CacheableObject.cacheValid][property]) {
+            return this[CacheableObject.cachedValue][property];
+          }
 
-    const compute = expose?.compute;
-    const transform = expose?.transform;
+          const dependencies = Object.create(null);
+          for (const key of expose.dependencies ?? []) {
+            switch (key) {
+              case 'this':
+                dependencies.this = this;
+                break;
 
-    if (flags.update && !transform) {
-      return null;
-    } else if (flags.update && compute) {
-      throw new Error(`Updating property ${property} has compute function, should be formatted as transform`);
-    } else if (!flags.update && !compute) {
-      throw new Error(`Exposed property ${property} does not update and is missing compute function`);
-    }
+              case 'thisProperty':
+                dependencies.thisProperty = property;
+                break;
 
-    let getAllDependencies;
+              default:
+                dependencies[key] = this[CacheableObject.updateValue][key];
+                break;
+            }
+          }
 
-    if (expose.dependencies?.length > 0) {
-      const dependencyKeys = expose.dependencies.slice();
-      const shouldReflectObject = dependencyKeys.includes('this');
-      const shouldReflectProperty = dependencyKeys.includes('thisProperty');
+          const value =
+            (flags.update
+              ? expose.transform(this[CacheableObject.updateValue][property], dependencies)
+              : expose.compute(dependencies));
 
-      getAllDependencies = () => {
-        const dependencies = Object.create(null);
+          this[CacheableObject.cachedValue][property] = value;
+          this[CacheableObject.cacheValid][property] = true;
 
-        for (const key of dependencyKeys) {
-          dependencies[key] = this.#propertyUpdateValues[key];
-        }
+          return value;
+        };
+      }
+
+      if (flags.expose) recordAsDependant: {
+        const dependantsMap = this[CacheableObject.propertyDependants];
 
-        if (shouldReflectObject) {
-          dependencies.this = this;
+        if (flags.update && expose?.transform) {
+          if (dependantsMap[property]) {
+            dependantsMap[property].push(property);
+          } else {
+            dependantsMap[property] = [property];
+          }
         }
 
-        if (shouldReflectProperty) {
-          dependencies.thisProperty = property;
+        for (const dependency of expose?.dependencies ?? []) {
+          switch (dependency) {
+            case 'this':
+            case 'thisProperty':
+              continue;
+
+            default: {
+              if (dependantsMap[dependency]) {
+                dependantsMap[dependency].push(property);
+              } else {
+                dependantsMap[dependency] = [property];
+              }
+            }
+          }
         }
+      }
 
-        return dependencies;
-      };
-    } else {
-      const dependencies = Object.create(null);
-      Object.freeze(dependencies);
-      getAllDependencies = () => dependencies;
+      Object.defineProperty(this.prototype, property, definition);
     }
 
-    if (flags.update) {
-      return () => transform(this.#propertyUpdateValues[property], getAllDependencies());
-    } else {
-      return () => compute(getAllDependencies());
-    }
+    this[CacheableObject.constructorFinalized] = true;
   }
 
-  #getExposeCheckCacheValidFunction(property) {
-    const {flags, expose} = this.#getPropertyDescriptor(property);
-
-    let valid = false;
-
-    const invalidate = () => {
-      valid = false;
-    };
-
-    const dependencyKeys = new Set(expose?.dependencies);
-
-    if (flags.update) {
-      dependencyKeys.add(property);
-    }
-
-    for (const key of dependencyKeys) {
-      if (this.#propertyUpdateCacheInvalidators[key]) {
-        this.#propertyUpdateCacheInvalidators[key].push(invalidate);
-      } else {
-        this.#propertyUpdateCacheInvalidators[key] = [invalidate];
-      }
-    }
+  static getPropertyDescriptor(property) {
+    return this[CacheableObject.propertyDescriptors][property];
+  }
 
-    return () => {
-      if (!valid) {
-        valid = true;
-        return false;
-      } else {
-        return true;
-      }
-    };
+  static hasPropertyDescriptor(property) {
+    return Object.hasOwn(this[CacheableObject.propertyDescriptors], property);
   }
 
   static cacheAllExposedProperties(obj) {
@@ -349,30 +214,12 @@ export default class CacheableObject {
     }
   }
 
-  static DEBUG_SLOW_TRACK_INVALID_PROPERTIES = false;
-  static _invalidAccesses = new Set();
-
-  static showInvalidAccesses() {
-    if (!this.DEBUG_SLOW_TRACK_INVALID_PROPERTIES) {
-      return;
-    }
-
-    if (!this._invalidAccesses.size) {
-      return;
-    }
-
-    console.log(`${this._invalidAccesses.size} unique invalid accesses:`);
-    for (const line of this._invalidAccesses) {
-      console.log(` - ${line}`);
-    }
-  }
-
   static getUpdateValue(object, key) {
-    if (!Object.hasOwn(object, key)) {
+    if (!object.constructor.hasPropertyDescriptor(key)) {
       return undefined;
     }
 
-    return object.#propertyUpdateValues[key] ?? null;
+    return object[CacheableObject.updateValue][key] ?? null;
   }
 
   static clone(object) {
@@ -384,7 +231,7 @@ export default class CacheableObject {
   }
 
   static copyUpdateValuesOnto(source, target) {
-    Object.assign(target, source.#propertyUpdateValues);
+    Object.assign(target, source[CacheableObject.updateValue]);
   }
 }
 
@@ -392,8 +239,22 @@ export class CacheableObjectPropertyValueError extends Error {
   [Symbol.for('hsmusic.aggregate.translucent')] = true;
 
   constructor(property, oldValue, newValue, options) {
+    let inspectOldValue, inspectNewValue;
+
+    try {
+      inspectOldValue = inspect(oldValue);
+    } catch {
+      inspectOldValue = colors.red(`(couldn't inspect)`);
+    }
+
+    try {
+      inspectNewValue = inspect(newValue);
+    } catch {
+      inspectNewValue = colors.red(`(couldn't inspect)`);
+    }
+
     super(
-      `Error setting ${colors.green(property)} (${inspect(oldValue)} -> ${inspect(newValue)})`,
+      `Error setting ${colors.green(property)} (${inspectOldValue} -> ${inspectNewValue})`,
       options);
 
     this.property = property;
diff --git a/src/data/checks.js b/src/data/checks.js
index 8f9f0305..3fcb6d3b 100644
--- a/src/data/checks.js
+++ b/src/data/checks.js
@@ -4,12 +4,11 @@ import {inspect as nodeInspect} from 'node:util';
 import {colors, ENABLE_COLOR} from '#cli';
 
 import CacheableObject from '#cacheable-object';
-import {replacerSpec, parseInput} from '#replacer';
+import {replacerSpec, parseContentNodes} from '#replacer';
 import {compareArrays, cut, cutStart, empty, getNestedProp, iterateMultiline}
   from '#sugar';
 import Thing from '#thing';
 import thingConstructors from '#things';
-import {combineWikiDataArrays, commentaryRegexCaseSensitive} from '#wiki-data';
 
 import {
   annotateErrorWithIndex,
@@ -50,7 +49,7 @@ export function reportDirectoryErrors(wikiData, {
     if (!thingData) continue;
 
     for (const thing of thingData) {
-      if (findSpec.include && !findSpec.include(thing)) {
+      if (findSpec.include && !findSpec.include(thing, thingConstructors)) {
         continue;
       }
 
@@ -185,18 +184,34 @@ export function filterReferenceErrors(wikiData, {
       groups: 'group',
       artTags: '_artTag',
       referencedArtworks: '_artwork',
-      commentary: '_commentary',
+      commentary: '_content',
+      creditingSources: '_content',
+    }],
+
+    ['artTagData', {
+      directDescendantArtTags: 'artTag',
+    }],
+
+    ['artworkData', {
+      referencedArtworks: '_artwork',
     }],
 
     ['flashData', {
-      commentary: '_commentary',
+      commentary: '_content',
+      creditingSources: '_content',
     }],
 
     ['groupCategoryData', {
       groups: 'group',
     }],
 
-    ['homepageLayout.rows', {
+    ['homepageLayout.sections.rows', {
+      _include: row => row.type === 'album carousel',
+      albums: 'album',
+    }],
+
+    ['homepageLayout.sections.rows', {
+      _include: row => row.type === 'album grid',
       sourceGroup: '_homepageSourceGroup',
       sourceAlbums: 'album',
     }],
@@ -210,20 +225,23 @@ export function filterReferenceErrors(wikiData, {
       flashes: 'flash',
     }],
 
-    ['groupData', {
-      serieses: '_serieses',
+    ['seriesData', {
+      albums: 'album',
     }],
 
     ['trackData', {
       artistContribs: '_contrib',
       contributorContribs: '_contrib',
       coverArtistContribs: '_contrib',
-      referencedTracks: '_trackNotRerelease',
-      sampledTracks: '_trackNotRerelease',
+      referencedTracks: '_trackMainReleasesOnly',
+      sampledTracks: '_trackMainReleasesOnly',
       artTags: '_artTag',
       referencedArtworks: '_artwork',
-      originalReleaseTrack: '_trackNotRerelease',
-      commentary: '_commentary',
+      mainReleaseTrack: '_trackMainReleasesOnly',
+      commentary: '_content',
+      creditingSources: '_content',
+      referencingSources: '_content',
+      lyrics: '_content',
     }],
 
     ['wikiInfo', {
@@ -237,21 +255,33 @@ export function filterReferenceErrors(wikiData, {
   const aggregate = openAggregate({message: `Errors validating between-thing references in data`});
   for (const [thingDataProp, propSpec] of referenceSpec) {
     const thingData = getNestedProp(wikiData, thingDataProp);
-    const things = Array.isArray(thingData) ? thingData : [thingData];
+    const things =
+      (Array.isArray(thingData)
+        ? thingData.flat(Infinity)
+        : [thingData]);
+
     aggregate.nest({message: `Reference errors in ${colors.green('wikiData.' + thingDataProp)}`}, ({nest}) => {
       for (const thing of things) {
+        if (propSpec._include && !propSpec._include(thing)) {
+          continue;
+        }
+
         nest({message: `Reference errors in ${inspect(thing)}`}, ({nest, push, filter}) => {
           for (const [property, findFnKey] of Object.entries(propSpec)) {
+            if (property === '_include') {
+              continue;
+            }
+
             let value = CacheableObject.getUpdateValue(thing, property);
             let writeProperty = true;
 
             switch (findFnKey) {
-              case '_commentary':
+              case '_content':
                 if (value) {
                   value =
-                    Array.from(value.matchAll(commentaryRegexCaseSensitive))
-                      .map(({groups}) => groups.artistReferences)
-                      .map(text => text.split(',').map(text => text.trim()));
+                    value.map(entry =>
+                      CacheableObject.getUpdateValue(entry, 'artists') ??
+                      []);
                 }
 
                 writeProperty = false;
@@ -265,15 +295,6 @@ export function filterReferenceErrors(wikiData, {
                 // need writing, humm...)
                 writeProperty = false;
                 break;
-
-              case '_serieses':
-                if (value) {
-                  // Doesn't report on which series has the error, but...
-                  value = value.flatMap(series => series.albums);
-                }
-
-                writeProperty = false;
-                break;
             }
 
             if (value === undefined) {
@@ -291,15 +312,12 @@ export function filterReferenceErrors(wikiData, {
               case '_artwork': {
                 const mixed =
                   find.mixed({
-                    album: find.albumWithArtwork,
-                    track: find.trackWithArtwork,
+                    album: find.albumPrimaryArtwork,
+                    track: find.trackPrimaryArtwork,
                   });
 
                 const data =
-                  combineWikiDataArrays([
-                    wikiData.albumData,
-                    wikiData.trackData,
-                  ]);
+                  wikiData.artworkData;
 
                 findFn = ref => mixed(ref.reference, data, {mode: 'error'});
 
@@ -310,7 +328,7 @@ export function filterReferenceErrors(wikiData, {
                 findFn = boundFind.artTag;
                 break;
 
-              case '_commentary':
+              case '_content':
                 findFn = findArtistOrAlias;
                 break;
 
@@ -328,37 +346,32 @@ export function filterReferenceErrors(wikiData, {
                 };
                 break;
 
-              case '_serieses':
-                findFn = boundFind.album;
-                break;
-
               case '_trackArtwork':
                 findFn = ref => boundFind.track(ref.reference);
                 break;
 
-              case '_trackNotRerelease':
+              case '_trackMainReleasesOnly':
                 findFn = trackRef => {
                   const track = boundFind.track(trackRef);
-                  const originalRef = track && CacheableObject.getUpdateValue(track, 'originalReleaseTrack');
+                  const mainRef = track && CacheableObject.getUpdateValue(track, 'mainReleaseTrack');
 
-                  if (originalRef) {
-                    // It's possible for the original to not actually exist, in this case.
-                    // It should still be reported since the 'Originally Released As' field
-                    // was present.
-                    const original = boundFind.track(originalRef, {mode: 'quiet'});
+                  if (mainRef) {
+                    // It's possible for the main release to not actually exist, in this case.
+                    // It should still be reported since the 'Main Release' field was present.
+                    const main = boundFind.track(mainRef, {mode: 'quiet'});
 
                     // Prefer references by name, but only if it's unambiguous.
-                    const originalByName =
-                      (original
-                        ? boundFind.track(original.name, {mode: 'quiet'})
+                    const mainByName =
+                      (main
+                        ? boundFind.track(main.name, {mode: 'quiet'})
                         : null);
 
                     const shouldBeMessage =
-                      (originalByName
-                        ? colors.green(original.name)
-                     : original
-                        ? colors.green('track:' + original.directory)
-                        : colors.green(originalRef));
+                      (mainByName
+                        ? colors.green(main.name)
+                     : main
+                        ? colors.green('track:' + main.directory)
+                        : colors.green(mainRef));
 
                     throw new Error(`Reference ${colors.red(trackRef)} is to a rerelease, should be ${shouldBeMessage}`);
                   }
@@ -372,7 +385,11 @@ export function filterReferenceErrors(wikiData, {
                 break;
             }
 
-            const suppress = fn => conditionallySuppressError(error => {
+            const suppress = fn => conditionallySuppressError(_error => {
+              // We're not suppressing any errors at the moment.
+              // An old suppression is kept below for reference.
+
+              /*
               if (property === 'sampledTracks') {
                 // Suppress "didn't match anything" errors in particular, just for samples.
                 // In hsmusic-data we have a lot of "stub" sample data which don't have
@@ -385,6 +402,7 @@ export function filterReferenceErrors(wikiData, {
                   return true;
                 }
               }
+              */
 
               return false;
             }, fn);
@@ -438,7 +456,7 @@ export function filterReferenceErrors(wikiData, {
                 }
               }
 
-              if (findFnKey === '_commentary') {
+              if (findFnKey === '_content') {
                 filter(
                   value, {message: errorMessage},
                   decorateErrorWithIndex(refs =>
@@ -539,16 +557,33 @@ export function reportContentTextErrors(wikiData, {
     description: 'description',
   };
 
+  const artworkShape = {
+    source: 'artwork source',
+    originDetails: 'artwork origin details',
+  };
+
   const commentaryShape = {
     body: 'commentary body',
-    artistDisplayText: 'commentary artist display text',
+    artistText: 'commentary artist text',
     annotation: 'commentary annotation',
   };
 
+  const lyricsShape = {
+    body: 'lyrics body',
+    artistText: 'lyrics artist text',
+    annotation: 'lyrics annotation',
+  };
+
   const contentTextSpec = [
     ['albumData', {
       additionalFiles: additionalFileShape,
       commentary: commentaryShape,
+      creditingSources: commentaryShape,
+      coverArtworks: artworkShape,
+    }],
+
+    ['artTagData', {
+      description: '_content',
     }],
 
     ['artistData', {
@@ -557,6 +592,8 @@ export function reportContentTextErrors(wikiData, {
 
     ['flashData', {
       commentary: commentaryShape,
+      creditingSources: commentaryShape,
+      coverArtwork: artworkShape,
     }],
 
     ['flashActData', {
@@ -586,10 +623,12 @@ export function reportContentTextErrors(wikiData, {
     ['trackData', {
       additionalFiles: additionalFileShape,
       commentary: commentaryShape,
-      creditSources: commentaryShape,
-      lyrics: '_content',
+      creditingSources: commentaryShape,
+      referencingSources: commentaryShape,
+      lyrics: lyricsShape,
       midiProjectFiles: additionalFileShape,
       sheetMusicFiles: additionalFileShape,
+      trackArtworks: artworkShape,
     }],
 
     ['wikiInfo', {
@@ -602,7 +641,7 @@ export function reportContentTextErrors(wikiData, {
   const findArtistOrAlias = bindFindArtistOrAlias(boundFind);
 
   function* processContent(input) {
-    const nodes = parseInput(input);
+    const nodes = parseContentNodes(input);
 
     for (const node of nodes) {
       const index = node.i;
@@ -659,7 +698,7 @@ export function reportContentTextErrors(wikiData, {
       } else if (node.type === 'external-link') {
         try {
           new URL(node.data.href);
-        } catch (error) {
+        } catch {
           yield {
             index, length,
             message:
@@ -710,8 +749,8 @@ export function reportContentTextErrors(wikiData, {
         for (const thing of things) {
           nest({message: `Content text errors in ${inspect(thing)}`}, ({nest, push}) => {
 
-            for (const [property, shape] of Object.entries(propSpec)) {
-              const value = thing[property];
+            for (let [property, shape] of Object.entries(propSpec)) {
+              let value = thing[property];
 
               if (value === undefined) {
                 push(new TypeError(`Property ${colors.red(property)} isn't valid for ${colors.green(thing.constructor.name)}`));
@@ -730,6 +769,31 @@ export function reportContentTextErrors(wikiData, {
               const topMessage =
                 `Content text errors` + fieldPropertyMessage;
 
+              const checkShapeEntries = (entry, callProcessContentOpts) => {
+                for (const [key, annotation] of Object.entries(shape)) {
+                  const value = entry[key];
+
+                  // TODO: This should be an undefined/null check, like above,
+                  // but it's not, because sometimes the stuff we're checking
+                  // here isn't actually coded as a Thing - so the properties
+                  // might really be undefined instead of null. Terrifying and
+                  // awful. And most of all, citation needed.
+                  if (!value) continue;
+
+                  callProcessContent({
+                    ...callProcessContentOpts,
+
+                    // TODO: `nest` isn't provided by `callProcessContentOpts`
+                    //`but `push` is - this is to match the old code, but
+                    // what's the deal here?
+                    nest,
+
+                    value,
+                    message: `Error in ${colors.green(annotation)}`,
+                  });
+                }
+              };
+
               if (shape === '_content') {
                 callProcessContent({
                   nest,
@@ -737,26 +801,18 @@ export function reportContentTextErrors(wikiData, {
                   value,
                   message: topMessage,
                 });
-              } else {
+              } else if (Array.isArray(value)) {
                 nest({message: topMessage}, ({push}) => {
                   for (const [index, entry] of value.entries()) {
-                    for (const [key, annotation] of Object.entries(shape)) {
-                      const value = entry[key];
-
-                      // TODO: Should this check undefined/null similar to above?
-                      if (!value) continue;
-
-                      callProcessContent({
-                        nest,
-                        push,
-                        value,
-                        message: `Error in ${colors.green(annotation)}`,
-                        annotateError: error =>
-                          annotateErrorWithIndex(error, index),
-                      });
-                    }
+                    checkShapeEntries(entry, {
+                      push,
+                      annotateError: error =>
+                        annotateErrorWithIndex(error, index),
+                    });
                   }
                 });
+              } else {
+                checkShapeEntries(value, {push});
               }
             }
           });
@@ -765,3 +821,49 @@ export function reportContentTextErrors(wikiData, {
     }
   });
 }
+
+export function reportOrphanedArtworks(wikiData) {
+  const aggregate =
+    openAggregate({message: `Artwork objects are orphaned`});
+
+  const assess = ({
+    message,
+    filterThing,
+    filterContribs,
+    link,
+  }) => {
+    aggregate.nest({message: `Orphaned ${message}`}, ({push}) => {
+      const ostensibleArtworks =
+        wikiData.artworkData
+          .filter(artwork =>
+            artwork.thing instanceof filterThing &&
+            artwork.artistContribsFromThingProperty === filterContribs);
+
+      const orphanedArtworks =
+        ostensibleArtworks
+          .filter(artwork => !artwork.thing[link].includes(artwork));
+
+      for (const artwork of orphanedArtworks) {
+        push(new Error(`Orphaned: ${inspect(artwork)}`));
+      }
+    });
+  };
+
+  const {Album, Track} = thingConstructors;
+
+  assess({
+    message: `album cover artworks`,
+    filterThing: Album,
+    filterContribs: 'coverArtistContribs',
+    link: 'coverArtworks',
+  });
+
+  assess({
+    message: `track artworks`,
+    filterThing: Track,
+    filterContribs: 'coverArtistContribs',
+    link: 'trackArtworks',
+  });
+
+  aggregate.close();
+}
diff --git a/src/data/composite/control-flow/flipFilter.js b/src/data/composite/control-flow/flipFilter.js
new file mode 100644
index 00000000..995bacad
--- /dev/null
+++ b/src/data/composite/control-flow/flipFilter.js
@@ -0,0 +1,36 @@
+// Flips a filter, so that each true item becomes false, and vice versa.
+// Overwrites the provided dependency.
+//
+// See also:
+//  - withAvailabilityFilter
+
+import {input, templateCompositeFrom} from '#composite';
+
+export default templateCompositeFrom({
+  annotation: `flipFilter`,
+
+  inputs: {
+    filter: input({type: 'array'}),
+  },
+
+  outputs: ({
+    [input.staticDependency('filter')]: filterDependency,
+  }) => [filterDependency ?? '#flippedFilter'],
+
+  steps: () => [
+    {
+      dependencies: [
+        input('filter'),
+        input.staticDependency('filter'),
+      ],
+
+      compute: (continuation, {
+        [input('filter')]: filter,
+        [input.staticDependency('filter')]: filterDependency,
+      }) => continuation({
+        [filterDependency ?? '#flippedFilter']:
+          filter.map(item => !item),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/index.js b/src/data/composite/control-flow/index.js
index 7e137a14..778dc66b 100644
--- a/src/data/composite/control-flow/index.js
+++ b/src/data/composite/control-flow/index.js
@@ -10,6 +10,7 @@ export {default as exposeDependency} from './exposeDependency.js';
 export {default as exposeDependencyOrContinue} from './exposeDependencyOrContinue.js';
 export {default as exposeUpdateValueOrContinue} from './exposeUpdateValueOrContinue.js';
 export {default as exposeWhetherDependencyAvailable} from './exposeWhetherDependencyAvailable.js';
+export {default as flipFilter} from './flipFilter.js';
 export {default as raiseOutputWithoutDependency} from './raiseOutputWithoutDependency.js';
 export {default as raiseOutputWithoutUpdateValue} from './raiseOutputWithoutUpdateValue.js';
 export {default as withAvailabilityFilter} from './withAvailabilityFilter.js';
diff --git a/src/data/composite/control-flow/withAvailabilityFilter.js b/src/data/composite/control-flow/withAvailabilityFilter.js
index cfea998e..fd93af71 100644
--- a/src/data/composite/control-flow/withAvailabilityFilter.js
+++ b/src/data/composite/control-flow/withAvailabilityFilter.js
@@ -4,6 +4,7 @@
 // Accepts the same mode options as withResultOfAvailabilityCheck.
 //
 // See also:
+//  - flipFilter
 //  - withFilteredList
 //  - withResultOfAvailabilityCheck
 //
diff --git a/src/data/composite/data/index.js b/src/data/composite/data/index.js
index 46a3dc81..05b59445 100644
--- a/src/data/composite/data/index.js
+++ b/src/data/composite/data/index.js
@@ -20,6 +20,7 @@ export {default as withMappedList} from './withMappedList.js';
 export {default as withSortedList} from './withSortedList.js';
 export {default as withStretchedList} from './withStretchedList.js';
 
+export {default as withLengthOfList} from './withLengthOfList.js';
 export {default as withPropertyFromList} from './withPropertyFromList.js';
 export {default as withPropertiesFromList} from './withPropertiesFromList.js';
 
diff --git a/src/data/composite/data/withFilteredList.js b/src/data/composite/data/withFilteredList.js
index 44c1661d..15ee3373 100644
--- a/src/data/composite/data/withFilteredList.js
+++ b/src/data/composite/data/withFilteredList.js
@@ -2,9 +2,6 @@
 // corresponding items in a list. Items which correspond to a truthy value
 // are kept, and the rest are excluded from the output list.
 //
-// If the flip option is set, only items corresponding with a *falsy* value in
-// the filter are kept.
-//
 // TODO: There should be two outputs - one for the items included according to
 // the filter, and one for the items excluded.
 //
@@ -22,28 +19,19 @@ export default templateCompositeFrom({
   inputs: {
     list: input({type: 'array'}),
     filter: input({type: 'array'}),
-
-    flip: input({
-      type: 'boolean',
-      defaultValue: false,
-    }),
   },
 
   outputs: ['#filteredList'],
 
   steps: () => [
     {
-      dependencies: [input('list'), input('filter'), input('flip')],
+      dependencies: [input('list'), input('filter')],
       compute: (continuation, {
         [input('list')]: list,
         [input('filter')]: filter,
-        [input('flip')]: flip,
       }) => continuation({
         '#filteredList':
-          list.filter((_item, index) =>
-            (flip
-              ? !filter[index]
-              :  filter[index])),
+          list.filter((_item, index) => filter[index]),
       }),
     },
   ],
diff --git a/src/data/composite/data/withLengthOfList.js b/src/data/composite/data/withLengthOfList.js
new file mode 100644
index 00000000..e67aa887
--- /dev/null
+++ b/src/data/composite/data/withLengthOfList.js
@@ -0,0 +1,54 @@
+import {input, templateCompositeFrom} from '#composite';
+
+function getOutputName({
+  [input.staticDependency('list')]: list,
+}) {
+  if (list && list.startsWith('#')) {
+    return `${list}.length`;
+  } else if (list) {
+    return `#${list}.length`;
+  } else {
+    return '#length';
+  }
+}
+
+export default templateCompositeFrom({
+  annotation: `withMappedList`,
+
+  inputs: {
+    list: input({type: 'array'}),
+  },
+
+  outputs: inputs => [getOutputName(inputs)],
+
+  steps: () => [
+    {
+      dependencies: [input.staticDependency('list')],
+      compute: (continuation, inputs) =>
+        continuation({'#output': getOutputName(inputs)}),
+    },
+
+    {
+      dependencies: [input('list')],
+      compute: (continuation, {
+        [input('list')]: list,
+      }) => continuation({
+        ['#value']:
+          (list === null
+            ? null
+            : list.length),
+      }),
+    },
+
+    {
+      dependencies: ['#output', '#value'],
+
+      compute: (continuation, {
+        ['#output']: output,
+        ['#value']: value,
+      }) => continuation({
+        [output]: value,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/data/withMappedList.js b/src/data/composite/data/withMappedList.js
index 0bc63a92..cd32058e 100644
--- a/src/data/composite/data/withMappedList.js
+++ b/src/data/composite/data/withMappedList.js
@@ -1,12 +1,16 @@
 // Applies a map function to each item in a list, just like a normal JavaScript
 // map.
 //
+// Pass a filter (e.g. from withAvailabilityFilter) to process only items
+// kept by the filter. Other items will be left as-is.
+//
 // See also:
 //  - withFilteredList
 //  - withSortedList
 //
 
 import {input, templateCompositeFrom} from '#composite';
+import {stitchArrays} from '#sugar';
 
 export default templateCompositeFrom({
   annotation: `withMappedList`,
@@ -14,19 +18,31 @@ export default templateCompositeFrom({
   inputs: {
     list: input({type: 'array'}),
     map: input({type: 'function'}),
+
+    filter: input({
+      type: 'array',
+      defaultValue: null,
+    }),
   },
 
   outputs: ['#mappedList'],
 
   steps: () => [
     {
-      dependencies: [input('list'), input('map')],
+      dependencies: [input('list'), input('map'), input('filter')],
       compute: (continuation, {
         [input('list')]: list,
         [input('map')]: mapFn,
+        [input('filter')]: filter,
       }) => continuation({
         ['#mappedList']:
-          list.map(mapFn),
+          stitchArrays({
+            item: list,
+            keep: filter ?? Array.from(list, () => true),
+          }).map(({item, keep}, index) =>
+              (keep
+                ? mapFn(item, index, list)
+                : item)),
       }),
     },
   ],
diff --git a/src/data/composite/data/withNearbyItemFromList.js b/src/data/composite/data/withNearbyItemFromList.js
index 83a8cc21..5e165219 100644
--- a/src/data/composite/data/withNearbyItemFromList.js
+++ b/src/data/composite/data/withNearbyItemFromList.js
@@ -9,6 +9,10 @@
 //  - If the 'valuePastEdge' input is provided, that value will be output
 //    instead of null.
 //
+//  - If the 'filter' input is provided, corresponding items will be skipped,
+//    and only (repeating `offset`) the next included in the filter will be
+//    returned.
+//
 // Both the list and item must be provided.
 //
 // See also:
@@ -16,7 +20,6 @@
 //
 
 import {input, templateCompositeFrom} from '#composite';
-import {atOffset} from '#sugar';
 
 import {raiseOutputWithoutDependency} from '#composite/control-flow';
 
@@ -28,9 +31,12 @@ export default templateCompositeFrom({
   inputs: {
     list: input({acceptsNull: false, type: 'array'}),
     item: input({acceptsNull: false}),
-
     offset: input({type: 'number'}),
+
     wrap: input({type: 'boolean', defaultValue: false}),
+    valuePastEdge: input({defaultValue: null}),
+
+    filter: input({defaultValue: null, type: 'array'}),
   },
 
   outputs: ['#nearbyItem'],
@@ -45,29 +51,55 @@ export default templateCompositeFrom({
       dependency: '#index',
       mode: input.value('index'),
 
-      output: input.value({
-        ['#nearbyItem']:
-          null,
-      }),
+      output: input.value({'#nearbyItem': null}),
     }),
 
     {
       dependencies: [
         input('list'),
         input('offset'),
+
         input('wrap'),
+        input('valuePastEdge'),
+
+        input('filter'),
+
         '#index',
       ],
 
       compute: (continuation, {
         [input('list')]: list,
         [input('offset')]: offset,
+
         [input('wrap')]: wrap,
+        [input('valuePastEdge')]: valuePastEdge,
+
+        [input('filter')]: filter,
+
         ['#index']: index,
-      }) => continuation({
-        ['#nearbyItem']:
-          atOffset(list, index, offset, {wrap}),
-      }),
+      }) => {
+        const startIndex = index;
+
+        do {
+          index += offset;
+
+          if (wrap) {
+            index = index % list.length;
+          } else if (index < 0) {
+            return continuation({'#nearbyItem': valuePastEdge});
+          } else if (index >= list.length) {
+            return continuation({'#nearbyItem': valuePastEdge});
+          }
+
+          if (filter && !filter[index]) {
+            continue;
+          }
+
+          return continuation({'#nearbyItem': list[index]});
+        } while (index !== startIndex);
+
+        return continuation({'#nearbyItem': null});
+      },
     },
   ],
 });
diff --git a/src/data/composite/data/withPropertyFromList.js b/src/data/composite/data/withPropertyFromList.js
index 65ebf77b..760095c2 100644
--- a/src/data/composite/data/withPropertyFromList.js
+++ b/src/data/composite/data/withPropertyFromList.js
@@ -5,11 +5,15 @@
 // original list are kept null here. Objects which don't have the specified
 // property are retained in-place as null.
 //
+// If the `internal` input is true, this reads the CacheableObject update value
+// of each object rather than its exposed value.
+//
 // See also:
 //  - withPropertiesFromList
 //  - withPropertyFromObject
 //
 
+import CacheableObject from '#cacheable-object';
 import {input, templateCompositeFrom} from '#composite';
 
 function getOutputName({list, property, prefix}) {
@@ -26,6 +30,7 @@ export default templateCompositeFrom({
     list: input({type: 'array'}),
     property: input({type: 'string'}),
     prefix: input.staticValue({type: 'string', defaultValue: null}),
+    internal: input({type: 'boolean', defaultValue: false}),
   },
 
   outputs: ({
@@ -37,13 +42,26 @@ export default templateCompositeFrom({
 
   steps: () => [
     {
-      dependencies: [input('list'), input('property')],
+      dependencies: [
+        input('list'),
+        input('property'),
+        input('internal'),
+      ],
+
       compute: (continuation, {
         [input('list')]: list,
         [input('property')]: property,
+        [input('internal')]: internal,
       }) => continuation({
         ['#values']:
-          list.map(item => item[property] ?? null),
+          list.map(item =>
+            (item === null
+              ? null
+           : internal
+              ? CacheableObject.getUpdateValue(item, property)
+                  ?? null
+              : item[property]
+                  ?? null)),
       }),
     },
 
diff --git a/src/data/composite/data/withPropertyFromObject.js b/src/data/composite/data/withPropertyFromObject.js
index 4f240506..7b452b99 100644
--- a/src/data/composite/data/withPropertyFromObject.js
+++ b/src/data/composite/data/withPropertyFromObject.js
@@ -13,6 +13,21 @@
 import CacheableObject from '#cacheable-object';
 import {input, templateCompositeFrom} from '#composite';
 
+function getOutputName({
+  [input.staticDependency('object')]: object,
+  [input.staticValue('property')]: property,
+}) {
+  if (object && property) {
+    if (object.startsWith('#')) {
+      return `${object}.${property}`;
+    } else {
+      return `#${object}.${property}`;
+    }
+  } else {
+    return '#value';
+  }
+}
+
 export default templateCompositeFrom({
   annotation: `withPropertyFromObject`,
 
@@ -22,15 +37,7 @@ export default templateCompositeFrom({
     internal: input({type: 'boolean', defaultValue: false}),
   },
 
-  outputs: ({
-    [input.staticDependency('object')]: object,
-    [input.staticValue('property')]: property,
-  }) =>
-    (object && property
-      ? (object.startsWith('#')
-          ? [`${object}.${property}`]
-          : [`#${object}.${property}`])
-      : ['#value']),
+  outputs: inputs => [getOutputName(inputs)],
 
   steps: () => [
     {
@@ -39,17 +46,8 @@ export default templateCompositeFrom({
         input.staticValue('property'),
       ],
 
-      compute: (continuation, {
-        [input.staticDependency('object')]: object,
-        [input.staticValue('property')]: property,
-      }) => continuation({
-        '#output':
-          (object && property
-            ? (object.startsWith('#')
-                ? `${object}.${property}`
-                : `#${object}.${property}`)
-            : '#value'),
-      }),
+      compute: (continuation, inputs) =>
+        continuation({'#output': getOutputName(inputs)}),
     },
 
     {
diff --git a/src/data/composite/things/album/index.js b/src/data/composite/things/album/index.js
index 8b5098f0..dfc6864f 100644
--- a/src/data/composite/things/album/index.js
+++ b/src/data/composite/things/album/index.js
@@ -1 +1,2 @@
+export {default as withHasCoverArt} from './withHasCoverArt.js';
 export {default as withTracks} from './withTracks.js';
diff --git a/src/data/composite/things/album/withHasCoverArt.js b/src/data/composite/things/album/withHasCoverArt.js
new file mode 100644
index 00000000..fd3f2894
--- /dev/null
+++ b/src/data/composite/things/album/withHasCoverArt.js
@@ -0,0 +1,64 @@
+// TODO: This shouldn't be coded as an Album-specific thing,
+// or even really to do with cover artworks in particular, either.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency, withResultOfAvailabilityCheck}
+  from '#composite/control-flow';
+import {fillMissingListItems, withFlattenedList, withPropertyFromList}
+  from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: 'withHasCoverArt',
+
+  outputs: ['#hasCoverArt'],
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: 'coverArtistContribs',
+      mode: input.value('empty'),
+    }),
+
+    {
+      dependencies: ['#availability'],
+      compute: (continuation, {
+        ['#availability']: availability,
+      }) =>
+        (availability
+          ? continuation.raiseOutput({
+              ['#hasCoverArt']: true,
+            })
+          : continuation()),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: 'coverArtworks',
+      mode: input.value('empty'),
+      output: input.value({'#hasCoverArt': false}),
+    }),
+
+    withPropertyFromList({
+      list: 'coverArtworks',
+      property: input.value('artistContribs'),
+      internal: input.value(true),
+    }),
+
+    // Since we're getting the update value for each artwork's artistContribs,
+    // it may not be set at all, and in that case won't be exposing as [].
+    fillMissingListItems({
+      list: '#coverArtworks.artistContribs',
+      fill: input.value([]),
+    }),
+
+    withFlattenedList({
+      list: '#coverArtworks.artistContribs',
+    }),
+
+    withResultOfAvailabilityCheck({
+      from: '#flattenedList',
+      mode: input.value('empty'),
+    }).outputs({
+      '#availability': '#hasCoverArt',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/album/withTracks.js b/src/data/composite/things/album/withTracks.js
index 348220e7..835ee570 100644
--- a/src/data/composite/things/album/withTracks.js
+++ b/src/data/composite/things/album/withTracks.js
@@ -1,7 +1,6 @@
 import {input, templateCompositeFrom} from '#composite';
 
 import {withFlattenedList, withPropertyFromList} from '#composite/data';
-import {withResolvedReferenceList} from '#composite/wiki-data';
 
 import {raiseOutputWithoutDependency} from '#composite/control-flow';
 
diff --git a/src/data/composite/things/art-tag/index.js b/src/data/composite/things/art-tag/index.js
new file mode 100644
index 00000000..bbd38293
--- /dev/null
+++ b/src/data/composite/things/art-tag/index.js
@@ -0,0 +1,2 @@
+export {default as withAllDescendantArtTags} from './withAllDescendantArtTags.js';
+export {default as withAncestorArtTagBaobabTree} from './withAncestorArtTagBaobabTree.js';
diff --git a/src/data/composite/things/art-tag/withAllDescendantArtTags.js b/src/data/composite/things/art-tag/withAllDescendantArtTags.js
new file mode 100644
index 00000000..795f96cd
--- /dev/null
+++ b/src/data/composite/things/art-tag/withAllDescendantArtTags.js
@@ -0,0 +1,44 @@
+// Gets all the art tags which descend from this one - that means its own direct
+// descendants, but also all the direct and indirect desceands of each of those!
+// The results aren't specially sorted, but they won't contain any duplicates
+// (for example if two descendant tags both route deeper to end up including
+// some of the same tags).
+
+import {input, templateCompositeFrom} from '#composite';
+import {unique} from '#sugar';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withResolvedReferenceList} from '#composite/wiki-data';
+import {soupyFind} from '#composite/wiki-properties';
+
+export default templateCompositeFrom({
+  annotation: `withAllDescendantArtTags`,
+
+  outputs: ['#allDescendantArtTags'],
+
+  steps: () => [
+    raiseOutputWithoutDependency({
+      dependency: 'directDescendantArtTags',
+      mode: input.value('empty'),
+      output: input.value({'#allDescendantArtTags': []})
+    }),
+
+    withResolvedReferenceList({
+      list: 'directDescendantArtTags',
+      find: soupyFind.input('artTag'),
+    }),
+
+    {
+      dependencies: ['#resolvedReferenceList'],
+      compute: (continuation, {
+        ['#resolvedReferenceList']: directDescendantArtTags,
+      }) => continuation({
+        ['#allDescendantArtTags']:
+          unique([
+            ...directDescendantArtTags,
+            ...directDescendantArtTags.flatMap(artTag => artTag.allDescendantArtTags),
+          ]),
+      }),
+    },
+  ],
+})
diff --git a/src/data/composite/things/art-tag/withAncestorArtTagBaobabTree.js b/src/data/composite/things/art-tag/withAncestorArtTagBaobabTree.js
new file mode 100644
index 00000000..e084a42b
--- /dev/null
+++ b/src/data/composite/things/art-tag/withAncestorArtTagBaobabTree.js
@@ -0,0 +1,46 @@
+// Gets all the art tags which are ancestors of this one as a "baobab tree" -
+// what you'd typically think of as roots are all up in the air! Since this
+// really is backwards from the way that the art tag tree is written in data,
+// chances are pretty good that there will be many of the exact same "leaf"
+// nodes - art tags which don't themselves have any ancestors. In the actual
+// data structure, each node is a Map, with keys for each ancestor and values
+// for each ancestor's own baobab (thus a branching structure, just like normal
+// trees in this regard).
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withReverseReferenceList} from '#composite/wiki-data';
+import {soupyReverse} from '#composite/wiki-properties';
+
+export default templateCompositeFrom({
+  annotation: `withAncestorArtTagBaobabTree`,
+
+  outputs: ['#ancestorArtTagBaobabTree'],
+
+  steps: () => [
+    withReverseReferenceList({
+      reverse: soupyReverse.input('artTagsWhichDirectlyAncestor'),
+    }).outputs({
+      ['#reverseReferenceList']: '#directAncestorArtTags',
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#directAncestorArtTags',
+      mode: input.value('empty'),
+      output: input.value({'#ancestorArtTagBaobabTree': new Map()}),
+    }),
+
+    {
+      dependencies: ['#directAncestorArtTags'],
+      compute: (continuation, {
+        ['#directAncestorArtTags']: directAncestorArtTags,
+      }) => continuation({
+        ['#ancestorArtTagBaobabTree']:
+          new Map(
+            directAncestorArtTags
+              .map(artTag => [artTag, artTag.ancestorArtTagBaobabTree])),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/artist/artistTotalDuration.js b/src/data/composite/things/artist/artistTotalDuration.js
index ff709f28..b8a205fe 100644
--- a/src/data/composite/things/artist/artistTotalDuration.js
+++ b/src/data/composite/things/artist/artistTotalDuration.js
@@ -2,8 +2,9 @@ import {input, templateCompositeFrom} from '#composite';
 
 import {exposeDependency} from '#composite/control-flow';
 import {withFilteredList, withPropertyFromList} from '#composite/data';
-import {withContributionListSums, withReverseContributionList}
+import {withContributionListSums, withReverseReferenceList}
   from '#composite/wiki-data';
+import {soupyReverse} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
   annotation: `artistTotalDuration`,
@@ -11,18 +12,16 @@ export default templateCompositeFrom({
   compose: false,
 
   steps: () => [
-    withReverseContributionList({
-      data: 'trackData',
-      list: input.value('artistContribs'),
+    withReverseReferenceList({
+      reverse: soupyReverse.input('trackArtistContributionsBy'),
     }).outputs({
-      '#reverseContributionList': '#contributionsAsArtist',
+      '#reverseReferenceList': '#contributionsAsArtist',
     }),
 
-    withReverseContributionList({
-      data: 'trackData',
-      list: input.value('contributorContribs'),
+    withReverseReferenceList({
+      reverse: soupyReverse.input('trackContributorContributionsBy'),
     }).outputs({
-      '#reverseContributionList': '#contributionsAsContributor',
+      '#reverseReferenceList': '#contributionsAsContributor',
     }),
 
     {
@@ -49,18 +48,18 @@ export default templateCompositeFrom({
 
     withPropertyFromList({
       list: '#allContributions.thing',
-      property: input.value('isOriginalRelease'),
+      property: input.value('isMainRelease'),
     }),
 
     withFilteredList({
       list: '#allContributions',
-      filter: '#allContributions.thing.isOriginalRelease',
+      filter: '#allContributions.thing.isMainRelease',
     }).outputs({
-      '#filteredList': '#originalContributions',
+      '#filteredList': '#mainReleaseContributions',
     }),
 
     withContributionListSums({
-      list: '#originalContributions',
+      list: '#mainReleaseContributions',
     }),
 
     exposeDependency({
diff --git a/src/data/composite/things/artwork/index.js b/src/data/composite/things/artwork/index.js
new file mode 100644
index 00000000..3693c10f
--- /dev/null
+++ b/src/data/composite/things/artwork/index.js
@@ -0,0 +1,5 @@
+export {default as withAttachedArtwork} from './withAttachedArtwork.js';
+export {default as withContainingArtworkList} from './withContainingArtworkList.js';
+export {default as withContribsFromAttachedArtwork} from './withContribsFromAttachedArtwork.js';
+export {default as withDate} from './withDate.js';
+export {default as withPropertyFromAttachedArtwork} from './withPropertyFromAttachedArtwork.js';
diff --git a/src/data/composite/things/artwork/withAttachedArtwork.js b/src/data/composite/things/artwork/withAttachedArtwork.js
new file mode 100644
index 00000000..d7c0d87b
--- /dev/null
+++ b/src/data/composite/things/artwork/withAttachedArtwork.js
@@ -0,0 +1,43 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {flipFilter, raiseOutputWithoutDependency}
+  from '#composite/control-flow';
+import {withNearbyItemFromList, withPropertyFromList} from '#composite/data';
+
+import withContainingArtworkList from './withContainingArtworkList.js';
+
+export default templateCompositeFrom({
+  annotaion: `withContribsFromMainArtwork`,
+
+  outputs: ['#attachedArtwork'],
+
+  steps: () => [
+    raiseOutputWithoutDependency({
+      dependency: 'attachAbove',
+      mode: input.value('falsy'),
+      output: input.value({'#attachedArtwork': null}),
+    }),
+
+    withContainingArtworkList(),
+
+    withPropertyFromList({
+      list: '#containingArtworkList',
+      property: input.value('attachAbove'),
+    }),
+
+    flipFilter({
+      filter: '#containingArtworkList.attachAbove',
+    }).outputs({
+      '#containingArtworkList.attachAbove': '#filterNotAttached',
+    }),
+
+    withNearbyItemFromList({
+      list: '#containingArtworkList',
+      item: input.myself(),
+      offset: input.value(-1),
+      filter: '#filterNotAttached',
+    }).outputs({
+      '#nearbyItem': '#attachedArtwork',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/artwork/withContainingArtworkList.js b/src/data/composite/things/artwork/withContainingArtworkList.js
new file mode 100644
index 00000000..9c928ffd
--- /dev/null
+++ b/src/data/composite/things/artwork/withContainingArtworkList.js
@@ -0,0 +1,46 @@
+// Gets the list of artworks which contains this one, which is functionally
+// equivalent to `this.thing[this.thingProperty]`. If the exposed value is not
+// a list at all (i.e. the property holds a single artwork), this composition
+// outputs null.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: `withContainingArtworkList`,
+
+  outputs: ['#containingArtworkList'],
+
+  steps: () => [
+    raiseOutputWithoutDependency({
+      dependency: 'thing',
+      output: input.value({'#containingArtworkList': null}),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: 'thingProperty',
+      output: input.value({'#containingArtworkList': null}),
+    }),
+
+    withPropertyFromObject({
+      object: 'thing',
+      property: 'thingProperty',
+    }).outputs({
+      '#value': '#containingValue',
+    }),
+
+    {
+      dependencies: ['#containingValue'],
+      compute: (continuation, {
+        ['#containingValue']: containingValue,
+      }) => continuation({
+        ['#containingArtworkList']:
+          (Array.isArray(containingValue)
+            ? containingValue
+            : null),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/artwork/withContribsFromAttachedArtwork.js b/src/data/composite/things/artwork/withContribsFromAttachedArtwork.js
new file mode 100644
index 00000000..e9425c95
--- /dev/null
+++ b/src/data/composite/things/artwork/withContribsFromAttachedArtwork.js
@@ -0,0 +1,27 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withRecontextualizedContributionList} from '#composite/wiki-data';
+
+import withPropertyFromAttachedArtwork from './withPropertyFromAttachedArtwork.js';
+
+export default templateCompositeFrom({
+  annotaion: `withContribsFromAttachedArtwork`,
+
+  outputs: ['#attachedArtwork.artistContribs'],
+
+  steps: () => [
+    withPropertyFromAttachedArtwork({
+      property: input.value('artistContribs'),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#attachedArtwork.artistContribs',
+      output: input.value({'#attachedArtwork.artistContribs': null}),
+    }),
+
+    withRecontextualizedContributionList({
+      list: '#attachedArtwork.artistContribs',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/artwork/withDate.js b/src/data/composite/things/artwork/withDate.js
new file mode 100644
index 00000000..5e05b814
--- /dev/null
+++ b/src/data/composite/things/artwork/withDate.js
@@ -0,0 +1,41 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: `withDate`,
+
+  inputs: {
+    from: input({
+      defaultDependency: 'date',
+      acceptsNull: true,
+    }),
+  },
+
+  outputs: ['#date'],
+
+  steps: () => [
+    {
+      dependencies: [input('from')],
+      compute: (continuation, {
+        [input('from')]: date,
+      }) =>
+        (date
+          ? continuation.raiseOutput({'#date': date})
+          : continuation()),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: 'dateFromThingProperty',
+      output: input.value({'#date': null}),
+    }),
+
+    withPropertyFromObject({
+      object: 'thing',
+      property: 'dateFromThingProperty',
+    }).outputs({
+      ['#value']: '#date',
+    }),
+  ],
+})
diff --git a/src/data/composite/things/artwork/withPropertyFromAttachedArtwork.js b/src/data/composite/things/artwork/withPropertyFromAttachedArtwork.js
new file mode 100644
index 00000000..a2f954b9
--- /dev/null
+++ b/src/data/composite/things/artwork/withPropertyFromAttachedArtwork.js
@@ -0,0 +1,65 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {withResultOfAvailabilityCheck} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+import withAttachedArtwork from './withAttachedArtwork.js';
+
+function getOutputName({
+  [input.staticValue('property')]: property,
+}) {
+  if (property) {
+    return `#attachedArtwork.${property}`;
+  } else {
+    return '#value';
+  }
+}
+
+export default templateCompositeFrom({
+  annotation: `withPropertyFromAttachedArtwork`,
+
+  inputs: {
+    property: input({type: 'string'}),
+  },
+
+  outputs: inputs => [getOutputName(inputs)],
+
+  steps: () => [
+    {
+      dependencies: [input.staticValue('property')],
+      compute: (continuation, inputs) =>
+        continuation({'#output': getOutputName(inputs)}),
+    },
+
+    withAttachedArtwork(),
+
+    withResultOfAvailabilityCheck({
+      from: '#attachedArtwork',
+    }),
+
+    {
+      dependencies: ['#availability', '#output'],
+      compute: (continuation, {
+        ['#availability']: availability,
+        ['#output']: output,
+      }) =>
+        (availability
+          ? continuation()
+          : continuation.raiseOutput({[output]: null})),
+    },
+
+    withPropertyFromObject({
+      object: '#attachedArtwork',
+      property: input('property'),
+    }),
+
+    {
+      dependencies: ['#value', '#output'],
+      compute: (continuation, {
+        ['#value']: value,
+        ['#output']: output,
+      }) =>
+        continuation.raiseOutput({[output]: value}),
+    },
+  ],
+});
diff --git a/src/data/composite/things/content/contentArtists.js b/src/data/composite/things/content/contentArtists.js
new file mode 100644
index 00000000..8d5db5a5
--- /dev/null
+++ b/src/data/composite/things/content/contentArtists.js
@@ -0,0 +1,40 @@
+import {input, templateCompositeFrom} from '#composite';
+import {validateReferenceList} from '#validators';
+
+import {exitWithoutDependency, exposeDependency}
+  from '#composite/control-flow';
+import {withResolvedReferenceList} from '#composite/wiki-data';
+import {soupyFind} from '#composite/wiki-properties';
+
+import withExpressedOrImplicitArtistReferences
+  from './helpers/withExpressedOrImplicitArtistReferences.js';
+
+export default templateCompositeFrom({
+  annotation: `contentArtists`,
+
+  compose: false,
+
+  update: {
+    validate: validateReferenceList('artist'),
+  },
+
+  steps: () => [
+    withExpressedOrImplicitArtistReferences({
+      from: input.updateValue(),
+    }),
+
+    exitWithoutDependency({
+      dependency: '#artistReferences',
+      value: input.value([]),
+    }),
+
+    withResolvedReferenceList({
+      list: '#artistReferences',
+      find: soupyFind.input('artist'),
+    }),
+
+    exposeDependency({
+      dependency: '#resolvedReferenceList',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/content/hasAnnotationPart.js b/src/data/composite/things/content/hasAnnotationPart.js
new file mode 100644
index 00000000..83d175e3
--- /dev/null
+++ b/src/data/composite/things/content/hasAnnotationPart.js
@@ -0,0 +1,25 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {exposeDependency} from '#composite/control-flow';
+
+import withHasAnnotationPart from './withHasAnnotationPart.js';
+
+export default templateCompositeFrom({
+  annotation: `hasAnnotationPart`,
+
+  compose: false,
+
+  inputs: {
+    part: input({type: 'string'}),
+  },
+
+  steps: () => [
+    withHasAnnotationPart({
+      part: input('part'),
+    }),
+
+    exposeDependency({
+      dependency: '#hasAnnotationPart',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/content/helpers/withExpressedOrImplicitArtistReferences.js b/src/data/composite/things/content/helpers/withExpressedOrImplicitArtistReferences.js
new file mode 100644
index 00000000..62799d43
--- /dev/null
+++ b/src/data/composite/things/content/helpers/withExpressedOrImplicitArtistReferences.js
@@ -0,0 +1,60 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withFilteredList, withMappedList} from '#composite/data';
+import {withContentNodes} from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `withExpressedOrImplicitArtistReferences`,
+
+  inputs: {
+    from: input({type: 'array', acceptsNull: true}),
+  },
+
+  outputs: ['#artistReferences'],
+
+  steps: () => [
+    {
+      dependencies: [input('from')],
+      compute: (continuation, {
+        [input('from')]: expressedArtistReferences,
+      }) =>
+        (expressedArtistReferences
+          ? continuation.raiseOutput({'#artistReferences': expressedArtistReferences})
+          : continuation()),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: 'artistText',
+      output: input.value({'#artistReferences': null}),
+    }),
+
+    withContentNodes({
+      from: 'artistText',
+    }),
+
+    withMappedList({
+      list: '#contentNodes',
+      map: input.value(node =>
+        node.type === 'tag' &&
+        node.data.replacerKey?.data === 'artist'),
+    }).outputs({
+      '#mappedList': '#artistTagFilter',
+    }),
+
+    withFilteredList({
+      list: '#contentNodes',
+      filter: '#artistTagFilter',
+    }).outputs({
+      '#filteredList': '#artistTags',
+    }),
+
+    withMappedList({
+      list: '#artistTags',
+      map: input.value(node =>
+        node.data.replacerValue[0].data),
+    }).outputs({
+      '#mappedList': '#artistReferences',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/content/index.js b/src/data/composite/things/content/index.js
new file mode 100644
index 00000000..4176337d
--- /dev/null
+++ b/src/data/composite/things/content/index.js
@@ -0,0 +1,7 @@
+export {default as contentArtists} from './contentArtists.js';
+export {default as hasAnnotationPart} from './hasAnnotationPart.js';
+export {default as withAnnotationParts} from './withAnnotationParts.js';
+export {default as withHasAnnotationPart} from './withHasAnnotationPart.js';
+export {default as withSourceText} from './withSourceText.js';
+export {default as withSourceURLs} from './withSourceURLs.js';
+export {default as withWebArchiveDate} from './withWebArchiveDate.js';
diff --git a/src/data/composite/things/content/withAnnotationParts.js b/src/data/composite/things/content/withAnnotationParts.js
new file mode 100644
index 00000000..6311b57a
--- /dev/null
+++ b/src/data/composite/things/content/withAnnotationParts.js
@@ -0,0 +1,93 @@
+import {input, templateCompositeFrom} from '#composite';
+import {transposeArrays} from '#sugar';
+import {is} from '#validators';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromList} from '#composite/data';
+import {splitContentNodesAround, withContentNodes} from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `withAnnotationParts`,
+
+  inputs: {
+    mode: input({
+      validate: is('strings', 'nodes'),
+    }),
+  },
+
+  outputs: ['#annotationParts'],
+
+  steps: () => [
+    raiseOutputWithoutDependency({
+      dependency: 'annotation',
+      output: input.value({'#annotationParts': []}),
+    }),
+
+    withContentNodes({
+      from: 'annotation',
+    }),
+
+    splitContentNodesAround({
+      nodes: '#contentNodes',
+      around: input.value(/, */g),
+    }),
+
+    {
+      dependencies: ['#contentNodeLists', input('mode')],
+      compute: (continuation, {
+        ['#contentNodeLists']: nodeLists,
+        [input('mode')]: mode,
+      }) =>
+        (mode === 'nodes'
+          ? continuation.raiseOutput({'#annotationParts': nodeLists})
+          : continuation()),
+    },
+
+    {
+      dependencies: ['#contentNodeLists'],
+
+      compute: (continuation, {
+        ['#contentNodeLists']: nodeLists,
+      }) => continuation({
+        ['#firstNodes']:
+          nodeLists.map(list => list.at(0)),
+
+        ['#lastNodes']:
+          nodeLists.map(list => list.at(-1)),
+      }),
+    },
+
+    withPropertyFromList({
+      list: '#firstNodes',
+      property: input.value('i'),
+    }).outputs({
+      '#firstNodes.i': '#startIndices',
+    }),
+
+    withPropertyFromList({
+      list: '#lastNodes',
+      property: input.value('iEnd'),
+    }).outputs({
+      '#lastNodes.iEnd': '#endIndices',
+    }),
+
+    {
+      dependencies: [
+        'annotation',
+        '#startIndices',
+        '#endIndices',
+      ],
+
+      compute: (continuation, {
+        ['annotation']: annotation,
+        ['#startIndices']: startIndices,
+        ['#endIndices']: endIndices,
+      }) => continuation({
+        ['#annotationParts']:
+          transposeArrays([startIndices, endIndices])
+            .map(([start, end]) =>
+              annotation.slice(start, end)),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/content/withHasAnnotationPart.js b/src/data/composite/things/content/withHasAnnotationPart.js
new file mode 100644
index 00000000..4af554f3
--- /dev/null
+++ b/src/data/composite/things/content/withHasAnnotationPart.js
@@ -0,0 +1,43 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+import withAnnotationParts from './withAnnotationParts.js';
+
+export default templateCompositeFrom({
+  annotation: `withHasAnnotationPart`,
+
+  inputs: {
+    part: input({type: 'string'}),
+  },
+
+  outputs: ['#hasAnnotationPart'],
+
+  steps: () => [
+    withAnnotationParts({
+      mode: input.value('strings'),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#annotationParts',
+      output: input.value({'#hasAnnotationPart': false}),
+    }),
+
+    {
+      dependencies: [
+        input('part'),
+        '#annotationParts',
+      ],
+
+      compute: (continuation, {
+        [input('part')]: search,
+        ['#annotationParts']: parts,
+      }) => continuation({
+        ['#hasAnnotationPart']:
+          parts.some(part =>
+            part.toLowerCase() ===
+            search.toLowerCase()),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/content/withSourceText.js b/src/data/composite/things/content/withSourceText.js
new file mode 100644
index 00000000..292306b7
--- /dev/null
+++ b/src/data/composite/things/content/withSourceText.js
@@ -0,0 +1,53 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+import withAnnotationParts from './withAnnotationParts.js';
+
+export default templateCompositeFrom({
+  annotation: `withSourceText`,
+
+  outputs: ['#sourceText'],
+
+  steps: () => [
+    withAnnotationParts({
+      mode: input.value('nodes'),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#annotationParts',
+      output: input.value({'#sourceText': null}),
+    }),
+
+    {
+      dependencies: ['#annotationParts'],
+      compute: (continuation, {
+        ['#annotationParts']: annotationParts,
+      }) => continuation({
+        ['#firstPartWithExternalLink']:
+          annotationParts
+            .find(nodes => nodes
+              .some(node => node.type === 'external-link')) ??
+          null,
+      }),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: '#firstPartWithExternalLink',
+      output: input.value({'#sourceText': null}),
+    }),
+
+    {
+      dependencies: ['annotation', '#firstPartWithExternalLink'],
+      compute: (continuation, {
+        ['annotation']: annotation,
+        ['#firstPartWithExternalLink']: nodes,
+      }) => continuation({
+        ['#sourceText']:
+          annotation.slice(
+            nodes.at(0).i,
+            nodes.at(-1).iEnd),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/content/withSourceURLs.js b/src/data/composite/things/content/withSourceURLs.js
new file mode 100644
index 00000000..f85ff9ea
--- /dev/null
+++ b/src/data/composite/things/content/withSourceURLs.js
@@ -0,0 +1,62 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withFilteredList, withMappedList} from '#composite/data';
+
+import withAnnotationParts from './withAnnotationParts.js';
+
+export default templateCompositeFrom({
+  annotation: `withSourceURLs`,
+
+  outputs: ['#sourceURLs'],
+
+  steps: () => [
+    withAnnotationParts({
+      mode: input.value('nodes'),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#annotationParts',
+      output: input.value({'#sourceURLs': []}),
+    }),
+
+    {
+      dependencies: ['#annotationParts'],
+      compute: (continuation, {
+        ['#annotationParts']: annotationParts,
+      }) => continuation({
+        ['#firstPartWithExternalLink']:
+          annotationParts
+            .find(nodes => nodes
+              .some(node => node.type === 'external-link')) ??
+          null,
+      }),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: '#firstPartWithExternalLink',
+      output: input.value({'#sourceURLs': []}),
+    }),
+
+    withMappedList({
+      list: '#firstPartWithExternalLink',
+      map: input.value(node => node.type === 'external-link'),
+    }).outputs({
+      '#mappedList': '#externalLinkFilter',
+    }),
+
+    withFilteredList({
+      list: '#firstPartWithExternalLink',
+      filter: '#externalLinkFilter',
+    }).outputs({
+      '#filteredList': '#externalLinks',
+    }),
+
+    withMappedList({
+      list: '#externalLinks',
+      map: input.value(node => node.data.href),
+    }).outputs({
+      '#mappedList': '#sourceURLs',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/content/withWebArchiveDate.js b/src/data/composite/things/content/withWebArchiveDate.js
new file mode 100644
index 00000000..3aaa4f64
--- /dev/null
+++ b/src/data/composite/things/content/withWebArchiveDate.js
@@ -0,0 +1,41 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+export default templateCompositeFrom({
+  annotation: `withWebArchiveDate`,
+
+  outputs: ['#webArchiveDate'],
+
+  steps: () => [
+    {
+      dependencies: ['annotation'],
+
+      compute: (continuation, {annotation}) =>
+        continuation({
+          ['#dateText']:
+            annotation
+              ?.match(/https?:\/\/web.archive.org\/web\/([0-9]{8,8})[0-9]*\//)
+              ?.[1] ??
+            null,
+        }),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: '#dateText',
+      output: input.value({['#webArchiveDate']: null}),
+    }),
+
+    {
+      dependencies: ['#dateText'],
+      compute: (continuation, {['#dateText']: dateText}) =>
+        continuation({
+          ['#webArchiveDate']:
+            new Date(
+              dateText.slice(0, 4) + '/' +
+              dateText.slice(4, 6) + '/' +
+              dateText.slice(6, 8)),
+        }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/contribution/inheritFromContributionPresets.js b/src/data/composite/things/contribution/inheritFromContributionPresets.js
index 82425b9c..a74e6db3 100644
--- a/src/data/composite/things/contribution/inheritFromContributionPresets.js
+++ b/src/data/composite/things/contribution/inheritFromContributionPresets.js
@@ -1,7 +1,7 @@
 import {input, templateCompositeFrom} from '#composite';
 
 import {raiseOutputWithoutDependency} from '#composite/control-flow';
-import {withPropertyFromList, withPropertyFromObject} from '#composite/data';
+import {withPropertyFromList} from '#composite/data';
 
 import withMatchingContributionPresets
   from './withMatchingContributionPresets.js';
diff --git a/src/data/composite/things/contribution/thingPropertyMatches.js b/src/data/composite/things/contribution/thingPropertyMatches.js
index 4a37f2cf..a678c3f5 100644
--- a/src/data/composite/things/contribution/thingPropertyMatches.js
+++ b/src/data/composite/things/contribution/thingPropertyMatches.js
@@ -12,19 +12,31 @@ export default templateCompositeFrom({
   },
 
   steps: () => [
+    {
+      dependencies: ['thing', 'thingProperty'],
+
+      compute: (continuation, {thing, thingProperty}) =>
+        continuation({
+          ['#thingProperty']:
+            (thing.constructor[Symbol.for('Thing.referenceType')] === 'artwork'
+              ? thing.artistContribsFromThingProperty
+              : thingProperty),
+        }),
+    },
+
     exitWithoutDependency({
-      dependency: 'thingProperty',
+      dependency: '#thingProperty',
       value: input.value(false),
     }),
 
     {
       dependencies: [
-        'thingProperty',
+        '#thingProperty',
         input('value'),
       ],
 
       compute: ({
-        ['thingProperty']: thingProperty,
+        ['#thingProperty']: thingProperty,
         [input('value')]: value,
       }) =>
         thingProperty === value,
diff --git a/src/data/composite/things/contribution/thingReferenceTypeMatches.js b/src/data/composite/things/contribution/thingReferenceTypeMatches.js
index 2ee811af..4042e78f 100644
--- a/src/data/composite/things/contribution/thingReferenceTypeMatches.js
+++ b/src/data/composite/things/contribution/thingReferenceTypeMatches.js
@@ -29,10 +29,37 @@ export default templateCompositeFrom({
         input('value'),
       ],
 
-      compute: ({
+      compute: (continuation, {
         ['#thing.constructor']: constructor,
         [input('value')]: value,
       }) =>
+        (constructor[Symbol.for('Thing.referenceType')] === value
+          ? continuation.exit(true)
+       : constructor[Symbol.for('Thing.referenceType')] === 'artwork'
+          ? continuation()
+          : continuation.exit(false)),
+    },
+
+    withPropertyFromObject({
+      object: 'thing',
+      property: input.value('thing'),
+    }),
+
+    withPropertyFromObject({
+      object: '#thing.thing',
+      property: input.value('constructor'),
+    }),
+
+    {
+      dependencies: [
+        '#thing.thing.constructor',
+        input('value'),
+      ],
+
+      compute: ({
+        ['#thing.thing.constructor']: constructor,
+        [input('value')]: value,
+      }) =>
         constructor[Symbol.for('Thing.referenceType')] === value,
     },
   ],
diff --git a/src/data/composite/things/contribution/withContainingReverseContributionList.js b/src/data/composite/things/contribution/withContainingReverseContributionList.js
index 56704c8b..175d6cbb 100644
--- a/src/data/composite/things/contribution/withContainingReverseContributionList.js
+++ b/src/data/composite/things/contribution/withContainingReverseContributionList.js
@@ -1,8 +1,12 @@
-// Get the artist's contribution list containing this property.
+// Get the artist's contribution list containing this property. Although that
+// list literally includes both dated and dateless contributions, here, if the
+// current contribution is dateless, the list is filtered to only include
+// dateless contributions from the same immediately nearby context.
 
 import {input, templateCompositeFrom} from '#composite';
 
-import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {raiseOutputWithoutDependency, withResultOfAvailabilityCheck}
+  from '#composite/control-flow';
 import {withPropertyFromObject} from '#composite/data';
 
 import withContributionArtist from './withContributionArtist.js';
@@ -34,7 +38,43 @@ export default templateCompositeFrom({
       object: '#artist',
       property: input('artistProperty'),
     }).outputs({
-      ['#value']: '#containingReverseContributionList',
+      ['#value']: '#list',
     }),
+
+    withResultOfAvailabilityCheck({
+      from: 'date',
+    }).outputs({
+      ['#availability']: '#hasDate',
+    }),
+
+    {
+      dependencies: ['#hasDate', '#list'],
+      compute: (continuation, {
+        ['#hasDate']: hasDate,
+        ['#list']: list,
+      }) =>
+        (hasDate
+          ? continuation.raiseOutput({
+              ['#containingReverseContributionList']:
+                list.filter(contrib => contrib.date),
+            })
+          : continuation({
+              ['#list']:
+                list.filter(contrib => !contrib.date),
+            })),
+    },
+
+    {
+      dependencies: ['#list', 'thing'],
+      compute: (continuation, {
+        ['#list']: list,
+        ['thing']: thing,
+      }) => continuation({
+        ['#containingReverseContributionList']:
+          (thing.album
+            ? list.filter(contrib => contrib.thing.album === thing.album)
+            : list),
+      }),
+    },
   ],
 });
diff --git a/src/data/composite/things/contribution/withContributionArtist.js b/src/data/composite/things/contribution/withContributionArtist.js
index 5a611c1a..5f81c716 100644
--- a/src/data/composite/things/contribution/withContributionArtist.js
+++ b/src/data/composite/things/contribution/withContributionArtist.js
@@ -1,8 +1,7 @@
 import {input, templateCompositeFrom} from '#composite';
-import find from '#find';
 
-import {withPropertyFromObject} from '#composite/data';
 import {withResolvedReference} from '#composite/wiki-data';
+import {soupyFind} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
   annotation: `withContributionArtist`,
@@ -17,16 +16,9 @@ export default templateCompositeFrom({
   outputs: ['#artist'],
 
   steps: () => [
-    withPropertyFromObject({
-      object: 'thing',
-      property: input.value('artistData'),
-      internal: input.value(true),
-    }),
-
     withResolvedReference({
       ref: input('ref'),
-      data: '#thing.artistData',
-      find: input.value(find.artist),
+      find: soupyFind.input('artist'),
     }).outputs({
       '#resolvedReference': '#artist',
     }),
diff --git a/src/data/composite/things/flash-act/withFlashSide.js b/src/data/composite/things/flash-act/withFlashSide.js
index 64daa1fb..e09f06e6 100644
--- a/src/data/composite/things/flash-act/withFlashSide.js
+++ b/src/data/composite/things/flash-act/withFlashSide.js
@@ -2,9 +2,10 @@
 // If there's no side whose list of flash acts includes this act, the output
 // dependency will be null.
 
-import {input, templateCompositeFrom} from '#composite';
+import {templateCompositeFrom} from '#composite';
 
 import {withUniqueReferencingThing} from '#composite/wiki-data';
+import {soupyReverse} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
   annotation: `withFlashSide`,
@@ -13,8 +14,7 @@ export default templateCompositeFrom({
 
   steps: () => [
     withUniqueReferencingThing({
-      data: 'flashSideData',
-      list: input.value('acts'),
+      reverse: soupyReverse.input('flashSidesWhoseActsInclude'),
     }).outputs({
       ['#uniqueReferencingThing']: '#flashSide',
     }),
diff --git a/src/data/composite/things/flash/withFlashAct.js b/src/data/composite/things/flash/withFlashAct.js
index 652b8bfb..87922aff 100644
--- a/src/data/composite/things/flash/withFlashAct.js
+++ b/src/data/composite/things/flash/withFlashAct.js
@@ -2,9 +2,10 @@
 // If there's no flash whose list of flashes includes this flash, the output
 // dependency will be null.
 
-import {input, templateCompositeFrom} from '#composite';
+import {templateCompositeFrom} from '#composite';
 
 import {withUniqueReferencingThing} from '#composite/wiki-data';
+import {soupyReverse} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
   annotation: `withFlashAct`,
@@ -13,8 +14,7 @@ export default templateCompositeFrom({
 
   steps: () => [
     withUniqueReferencingThing({
-      data: 'flashActData',
-      list: input.value('flashes'),
+      reverse: soupyReverse.input('flashActsWhoseFlashesInclude'),
     }).outputs({
       ['#uniqueReferencingThing']: '#flashAct',
     }),
diff --git a/src/data/composite/things/track-section/index.js b/src/data/composite/things/track-section/index.js
index 3202ed49..f11a2ab5 100644
--- a/src/data/composite/things/track-section/index.js
+++ b/src/data/composite/things/track-section/index.js
@@ -1 +1,3 @@
 export {default as withAlbum} from './withAlbum.js';
+export {default as withContinueCountingFrom} from './withContinueCountingFrom.js';
+export {default as withStartCountingFrom} from './withStartCountingFrom.js';
diff --git a/src/data/composite/things/track-section/withAlbum.js b/src/data/composite/things/track-section/withAlbum.js
index a4dfff0d..e257062e 100644
--- a/src/data/composite/things/track-section/withAlbum.js
+++ b/src/data/composite/things/track-section/withAlbum.js
@@ -1,8 +1,9 @@
 // Gets the track section's album.
 
-import {input, templateCompositeFrom} from '#composite';
+import {templateCompositeFrom} from '#composite';
 
 import {withUniqueReferencingThing} from '#composite/wiki-data';
+import {soupyReverse} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
   annotation: `withAlbum`,
@@ -11,8 +12,7 @@ export default templateCompositeFrom({
 
   steps: () => [
     withUniqueReferencingThing({
-      data: 'albumData',
-      list: input.value('trackSections'),
+      reverse: soupyReverse.input('albumsWhoseTrackSectionsInclude'),
     }).outputs({
       ['#uniqueReferencingThing']: '#album',
     }),
diff --git a/src/data/composite/things/track-section/withContinueCountingFrom.js b/src/data/composite/things/track-section/withContinueCountingFrom.js
new file mode 100644
index 00000000..0ca52b6c
--- /dev/null
+++ b/src/data/composite/things/track-section/withContinueCountingFrom.js
@@ -0,0 +1,25 @@
+import {templateCompositeFrom} from '#composite';
+
+import withStartCountingFrom from './withStartCountingFrom.js';
+
+export default templateCompositeFrom({
+  annotation: `withContinueCountingFrom`,
+
+  outputs: ['#continueCountingFrom'],
+
+  steps: () => [
+    withStartCountingFrom(),
+
+    {
+      dependencies: ['#startCountingFrom', 'tracks'],
+      compute: (continuation, {
+        ['#startCountingFrom']: startCountingFrom,
+        ['tracks']: tracks,
+      }) => continuation({
+        ['#continueCountingFrom']:
+          startCountingFrom +
+          tracks.length,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/track-section/withStartCountingFrom.js b/src/data/composite/things/track-section/withStartCountingFrom.js
new file mode 100644
index 00000000..ef345327
--- /dev/null
+++ b/src/data/composite/things/track-section/withStartCountingFrom.js
@@ -0,0 +1,64 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withNearbyItemFromList, withPropertyFromObject} from '#composite/data';
+
+import withAlbum from './withAlbum.js';
+
+export default templateCompositeFrom({
+  annotation: `withStartCountingFrom`,
+
+  inputs: {
+    from: input({
+      type: 'number',
+      defaultDependency: 'startCountingFrom',
+      acceptsNull: true,
+    }),
+  },
+
+  outputs: ['#startCountingFrom'],
+
+  steps: () => [
+    {
+      dependencies: [input('from')],
+      compute: (continuation, {
+        [input('from')]: from,
+      }) =>
+        (from === null
+          ? continuation()
+          : continuation.raiseOutput({'#startCountingFrom': from})),
+    },
+
+    withAlbum(),
+
+    raiseOutputWithoutDependency({
+      dependency: '#album',
+      output: input.value({'#startCountingFrom': 1}),
+    }),
+
+    withPropertyFromObject({
+      object: '#album',
+      property: input.value('trackSections'),
+    }),
+
+    withNearbyItemFromList({
+      list: '#album.trackSections',
+      item: input.myself(),
+      offset: input.value(-1),
+    }).outputs({
+      '#nearbyItem': '#previousTrackSection',
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#previousTrackSection',
+      output: input.value({'#startCountingFrom': 1}),
+    }),
+
+    withPropertyFromObject({
+      object: '#previousTrackSection',
+      property: input.value('continueCountingFrom'),
+    }).outputs({
+      '#previousTrackSection.continueCountingFrom': '#startCountingFrom',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/track/index.js b/src/data/composite/things/track/index.js
index 05ccaaba..e789e736 100644
--- a/src/data/composite/things/track/index.js
+++ b/src/data/composite/things/track/index.js
@@ -1,16 +1,17 @@
 export {default as exitWithoutUniqueCoverArt} from './exitWithoutUniqueCoverArt.js';
-export {default as inheritContributionListFromOriginalRelease} from './inheritContributionListFromOriginalRelease.js';
-export {default as inheritFromOriginalRelease} from './inheritFromOriginalRelease.js';
-export {default as trackReverseReferenceList} from './trackReverseReferenceList.js';
-export {default as withAlbum} from './withAlbum.js';
+export {default as inheritContributionListFromMainRelease} from './inheritContributionListFromMainRelease.js';
+export {default as inheritFromMainRelease} from './inheritFromMainRelease.js';
+export {default as withAllReleases} from './withAllReleases.js';
 export {default as withAlwaysReferenceByDirectory} from './withAlwaysReferenceByDirectory.js';
 export {default as withContainingTrackSection} from './withContainingTrackSection.js';
+export {default as withCoverArtistContribs} from './withCoverArtistContribs.js';
 export {default as withDate} from './withDate.js';
 export {default as withDirectorySuffix} from './withDirectorySuffix.js';
 export {default as withHasUniqueCoverArt} from './withHasUniqueCoverArt.js';
-export {default as withOriginalRelease} from './withOriginalRelease.js';
+export {default as withMainRelease} from './withMainRelease.js';
 export {default as withOtherReleases} from './withOtherReleases.js';
 export {default as withPropertyFromAlbum} from './withPropertyFromAlbum.js';
-export {default as withPropertyFromOriginalRelease} from './withPropertyFromOriginalRelease.js';
+export {default as withPropertyFromMainRelease} from './withPropertyFromMainRelease.js';
 export {default as withSuffixDirectoryFromAlbum} from './withSuffixDirectoryFromAlbum.js';
 export {default as withTrackArtDate} from './withTrackArtDate.js';
+export {default as withTrackNumber} from './withTrackNumber.js';
diff --git a/src/data/composite/things/track/inheritContributionListFromOriginalRelease.js b/src/data/composite/things/track/inheritContributionListFromMainRelease.js
index f4ae3ddb..89252feb 100644
--- a/src/data/composite/things/track/inheritContributionListFromOriginalRelease.js
+++ b/src/data/composite/things/track/inheritContributionListFromMainRelease.js
@@ -1,5 +1,5 @@
-// Like inheritFromOriginalRelease, but tuned for contributions.
-// Recontextualized contributions for this track.
+// Like inheritFromMainRelease, but tuned for contributions.
+// Recontextualizes contributions for this track.
 
 import {input, templateCompositeFrom} from '#composite';
 
@@ -9,36 +9,36 @@ import {withRecontextualizedContributionList, withRedatedContributionList}
   from '#composite/wiki-data';
 
 import withDate from './withDate.js';
-import withPropertyFromOriginalRelease
-  from './withPropertyFromOriginalRelease.js';
+import withPropertyFromMainRelease
+  from './withPropertyFromMainRelease.js';
 
 export default templateCompositeFrom({
-  annotation: `inheritContributionListFromOriginalRelease`,
+  annotation: `inheritContributionListFromMainRelease`,
 
   steps: () => [
-    withPropertyFromOriginalRelease({
+    withPropertyFromMainRelease({
       property: input.thisProperty(),
       notFoundValue: input.value([]),
     }),
 
     raiseOutputWithoutDependency({
-      dependency: '#isRerelease',
+      dependency: '#isSecondaryRelease',
       mode: input.value('falsy'),
     }),
 
     withRecontextualizedContributionList({
-      list: '#originalValue',
+      list: '#mainReleaseValue',
     }),
 
     withDate(),
 
     withRedatedContributionList({
-      list: '#originalValue',
+      list: '#mainReleaseValue',
       date: '#date',
     }),
 
     exposeDependency({
-      dependency: '#originalValue',
+      dependency: '#mainReleaseValue',
     }),
   ],
 });
diff --git a/src/data/composite/things/track/inheritFromOriginalRelease.js b/src/data/composite/things/track/inheritFromMainRelease.js
index 38ab06be..b1cbb65e 100644
--- a/src/data/composite/things/track/inheritFromOriginalRelease.js
+++ b/src/data/composite/things/track/inheritFromMainRelease.js
@@ -1,9 +1,9 @@
 // Early exits with the value for the same property as specified on the
-// original release, if this track is a rerelease, and otherwise continues
+// main release, if this track is a secondary release, and otherwise continues
 // without providing any further dependencies.
 //
-// Like withOriginalRelease, this will early exit (with notFoundValue) if the
-// original release is specified by reference and that reference doesn't
+// Like withMainRelease, this will early exit (with notFoundValue) if the
+// main release is specified by reference and that reference doesn't
 // resolve to anything.
 
 import {input, templateCompositeFrom} from '#composite';
@@ -11,11 +11,11 @@ import {input, templateCompositeFrom} from '#composite';
 import {exposeDependency, raiseOutputWithoutDependency}
   from '#composite/control-flow';
 
-import withPropertyFromOriginalRelease
-  from './withPropertyFromOriginalRelease.js';
+import withPropertyFromMainRelease
+  from './withPropertyFromMainRelease.js';
 
 export default templateCompositeFrom({
-  annotation: `inheritFromOriginalRelease`,
+  annotation: `inheritFromMainRelease`,
 
   inputs: {
     notFoundValue: input({
@@ -24,18 +24,18 @@ export default templateCompositeFrom({
   },
 
   steps: () => [
-    withPropertyFromOriginalRelease({
+    withPropertyFromMainRelease({
       property: input.thisProperty(),
       notFoundValue: input('notFoundValue'),
     }),
 
     raiseOutputWithoutDependency({
-      dependency: '#isRerelease',
+      dependency: '#isSecondaryRelease',
       mode: input.value('falsy'),
     }),
 
     exposeDependency({
-      dependency: '#originalValue',
+      dependency: '#mainReleaseValue',
     }),
   ],
 });
diff --git a/src/data/composite/things/track/trackAdditionalNameList.js b/src/data/composite/things/track/trackAdditionalNameList.js
deleted file mode 100644
index 65a2263d..00000000
--- a/src/data/composite/things/track/trackAdditionalNameList.js
+++ /dev/null
@@ -1,38 +0,0 @@
-// Compiles additional names from various sources.
-
-import {input, templateCompositeFrom} from '#composite';
-import {isAdditionalNameList} from '#validators';
-
-import withInferredAdditionalNames from './withInferredAdditionalNames.js';
-import withSharedAdditionalNames from './withSharedAdditionalNames.js';
-
-export default templateCompositeFrom({
-  annotation: `trackAdditionalNameList`,
-
-  compose: false,
-
-  update: {validate: isAdditionalNameList},
-
-  steps: () => [
-    withInferredAdditionalNames(),
-    withSharedAdditionalNames(),
-
-    {
-      dependencies: [
-        '#inferredAdditionalNames',
-        '#sharedAdditionalNames',
-        input.updateValue(),
-      ],
-
-      compute: ({
-        ['#inferredAdditionalNames']: inferredAdditionalNames,
-        ['#sharedAdditionalNames']: sharedAdditionalNames,
-        [input.updateValue()]: providedAdditionalNames,
-      }) => [
-        ...providedAdditionalNames ?? [],
-        ...sharedAdditionalNames,
-        ...inferredAdditionalNames,
-      ],
-    },
-  ],
-});
diff --git a/src/data/composite/things/track/trackReverseReferenceList.js b/src/data/composite/things/track/trackReverseReferenceList.js
deleted file mode 100644
index 44940ae7..00000000
--- a/src/data/composite/things/track/trackReverseReferenceList.js
+++ /dev/null
@@ -1,38 +0,0 @@
-// Like a normal reverse reference list ("objects which reference this object
-// under a specified property"), only excluding rereleases from the possible
-// outputs. While it's useful to travel from a rerelease to the tracks it
-// references, rereleases aren't generally relevant from the perspective of
-// the tracks *being* referenced. Apart from hiding rereleases from lists on
-// the site, it also excludes keeps them from relational data processing, such
-// as on the "Tracks - by Times Referenced" listing page.
-
-import {input, templateCompositeFrom} from '#composite';
-import {withReverseReferenceList} from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `trackReverseReferenceList`,
-
-  compose: false,
-
-  inputs: {
-    list: input({type: 'string'}),
-  },
-
-  steps: () => [
-    withReverseReferenceList({
-      data: 'trackData',
-      list: input('list'),
-    }),
-
-    {
-      flags: {expose: true},
-      expose: {
-        dependencies: ['#reverseReferenceList'],
-        compute: ({
-          ['#reverseReferenceList']: reverseReferenceList,
-        }) =>
-          reverseReferenceList.filter(track => !track.originalReleaseTrack),
-      },
-    },
-  ],
-});
diff --git a/src/data/composite/things/track/withAlbum.js b/src/data/composite/things/track/withAlbum.js
deleted file mode 100644
index 03b840d4..00000000
--- a/src/data/composite/things/track/withAlbum.js
+++ /dev/null
@@ -1,22 +0,0 @@
-// Gets the track's album. This will early exit if albumData is missing.
-// If there's no album whose list of tracks includes this track, the output
-// dependency will be null.
-
-import {input, templateCompositeFrom} from '#composite';
-
-import {withUniqueReferencingThing} from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `withAlbum`,
-
-  outputs: ['#album'],
-
-  steps: () => [
-    withUniqueReferencingThing({
-      data: 'albumData',
-      list: input.value('tracks'),
-    }).outputs({
-      ['#uniqueReferencingThing']: '#album',
-    }),
-  ],
-});
diff --git a/src/data/composite/things/track/withAllReleases.js b/src/data/composite/things/track/withAllReleases.js
new file mode 100644
index 00000000..891db102
--- /dev/null
+++ b/src/data/composite/things/track/withAllReleases.js
@@ -0,0 +1,46 @@
+// Gets all releases of the current track. All items of the outputs are
+// distinct Track objects; one track is the main release; all else are
+// secondary releases of that main release; and one item, which may be
+// the main release or one of the secondary releases, is the current
+// track. The results are sorted by date, and it is possible that the
+// main release is not actually the earliest/first.
+
+import {input, templateCompositeFrom} from '#composite';
+import {sortByDate} from '#sort';
+
+import {withPropertyFromObject} from '#composite/data';
+
+import withMainRelease from './withMainRelease.js';
+
+export default templateCompositeFrom({
+  annotation: `withAllReleases`,
+
+  outputs: ['#allReleases'],
+
+  steps: () => [
+    withMainRelease({
+      selfIfMain: input.value(true),
+      notFoundValue: input.value([]),
+    }),
+
+    // We don't talk about bruno no no
+    // Yes, this can perform a normal access equivalent to
+    // `this.secondaryReleases` from within a data composition.
+    // Oooooooooooooooooooooooooooooooooooooooooooooooo
+    withPropertyFromObject({
+      object: '#mainRelease',
+      property: input.value('secondaryReleases'),
+    }),
+
+    {
+      dependencies: ['#mainRelease', '#mainRelease.secondaryReleases'],
+      compute: (continuation, {
+        ['#mainRelease']: mainRelease,
+        ['#mainRelease.secondaryReleases']: secondaryReleases,
+      }) => continuation({
+        ['#allReleases']:
+          sortByDate([mainRelease, ...secondaryReleases]),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/track/withAlwaysReferenceByDirectory.js b/src/data/composite/things/track/withAlwaysReferenceByDirectory.js
index e01720b4..87edf21e 100644
--- a/src/data/composite/things/track/withAlwaysReferenceByDirectory.js
+++ b/src/data/composite/things/track/withAlwaysReferenceByDirectory.js
@@ -16,6 +16,8 @@ import {
   exposeUpdateValueOrContinue,
 } from '#composite/control-flow';
 
+import withPropertyFromAlbum from './withPropertyFromAlbum.js';
+
 export default templateCompositeFrom({
   annotation: `withAlwaysReferenceByDirectory`,
 
@@ -26,19 +28,7 @@ export default templateCompositeFrom({
       validate: input.value(isBoolean),
     }),
 
-    // withAlwaysReferenceByDirectory is sort of a fragile area - we can't
-    // find the track's album the normal way because albums' track lists
-    // recurse back into alwaysReferenceByDirectory!
-    withResolvedReference({
-      ref: 'dataSourceAlbum',
-      data: 'albumData',
-      find: input.value(find.album),
-    }).outputs({
-      '#resolvedReference': '#album',
-    }),
-
-    withPropertyFromObject({
-      object: '#album',
+    withPropertyFromAlbum({
       property: input.value('alwaysReferenceTracksByDirectory'),
     }),
 
@@ -51,7 +41,7 @@ export default templateCompositeFrom({
 
     // Remaining code is for defaulting to true if this track is a rerelease of
     // another with the same name, so everything further depends on access to
-    // trackData as well as originalReleaseTrack.
+    // trackData as well as mainReleaseTrack.
 
     exitWithoutDependency({
       dependency: 'trackData',
@@ -60,45 +50,46 @@ export default templateCompositeFrom({
     }),
 
     exitWithoutDependency({
-      dependency: 'originalReleaseTrack',
+      dependency: 'mainReleaseTrack',
       value: input.value(false),
     }),
 
-    // It's necessary to use the custom trackOriginalReleasesOnly find function
+    // It's necessary to use the custom trackMainReleasesOnly find function
     // here, so as to avoid recursion issues - the find.track() function depends
     // on accessing each track's alwaysReferenceByDirectory, which means it'll
     // hit *this track* - and thus this step - and end up recursing infinitely.
-    // By definition, find.trackOriginalReleasesOnly excludes tracks which have
-    // an originalReleaseTrack update value set, which means even though it does
+    // By definition, find.trackMainReleasesOnly excludes tracks which have
+    // an mainReleaseTrack update value set, which means even though it does
     // still access each of tracks' `alwaysReferenceByDirectory` property, it
     // won't access that of *this* track - it will never proceed past the
     // `exitWithoutDependency` step directly above, so there's no opportunity
     // for recursion.
     withResolvedReference({
-      ref: 'originalReleaseTrack',
+      ref: 'mainReleaseTrack',
       data: 'trackData',
-      find: input.value(find.trackOriginalReleasesOnly),
+      find: input.value(find.trackMainReleasesOnly),
     }).outputs({
-      '#resolvedReference': '#originalRelease',
+      '#resolvedReference': '#mainRelease',
     }),
 
     exitWithoutDependency({
-      dependency: '#originalRelease',
+      dependency: '#mainRelease',
       value: input.value(false),
     }),
 
     withPropertyFromObject({
-      object: '#originalRelease',
+      object: '#mainRelease',
       property: input.value('name'),
     }),
 
     {
-      dependencies: ['name', '#originalRelease.name'],
+      dependencies: ['name', '#mainRelease.name'],
       compute: (continuation, {
         name,
-        ['#originalRelease.name']: originalName,
+        ['#mainRelease.name']: mainReleaseName,
       }) => continuation({
-        ['#alwaysReferenceByDirectory']: name === originalName,
+        ['#alwaysReferenceByDirectory']:
+          name === mainReleaseName,
       }),
     },
   ],
diff --git a/src/data/composite/things/track/withContainingTrackSection.js b/src/data/composite/things/track/withContainingTrackSection.js
index 9bbd9bd5..3d4d081e 100644
--- a/src/data/composite/things/track/withContainingTrackSection.js
+++ b/src/data/composite/things/track/withContainingTrackSection.js
@@ -1,8 +1,9 @@
 // Gets the track section containing this track from its album's track list.
 
-import {input, templateCompositeFrom} from '#composite';
+import {templateCompositeFrom} from '#composite';
 
 import {withUniqueReferencingThing} from '#composite/wiki-data';
+import {soupyReverse} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
   annotation: `withContainingTrackSection`,
@@ -11,8 +12,7 @@ export default templateCompositeFrom({
 
   steps: () => [
     withUniqueReferencingThing({
-      data: 'trackSectionData',
-      list: input.value('tracks'),
+      reverse: soupyReverse.input('trackSectionsWhichInclude'),
     }).outputs({
       ['#uniqueReferencingThing']: '#trackSection',
     }),
diff --git a/src/data/composite/things/track/withCoverArtistContribs.js b/src/data/composite/things/track/withCoverArtistContribs.js
new file mode 100644
index 00000000..9057cfeb
--- /dev/null
+++ b/src/data/composite/things/track/withCoverArtistContribs.js
@@ -0,0 +1,73 @@
+import {input, templateCompositeFrom} from '#composite';
+import {isContributionList} from '#validators';
+
+import {exposeDependencyOrContinue} from '#composite/control-flow';
+
+import {
+  withRecontextualizedContributionList,
+  withRedatedContributionList,
+  withResolvedContribs,
+} from '#composite/wiki-data';
+
+import exitWithoutUniqueCoverArt from './exitWithoutUniqueCoverArt.js';
+import withPropertyFromAlbum from './withPropertyFromAlbum.js';
+import withTrackArtDate from './withTrackArtDate.js';
+
+export default templateCompositeFrom({
+  annotation: `withCoverArtistContribs`,
+
+  inputs: {
+    from: input({
+      defaultDependency: 'coverArtistContribs',
+      validate: isContributionList,
+      acceptsNull: true,
+    }),
+  },
+
+  outputs: ['#coverArtistContribs'],
+
+  steps: () => [
+    exitWithoutUniqueCoverArt({
+      value: input.value([]),
+    }),
+
+    withTrackArtDate(),
+
+    withResolvedContribs({
+      from: input('from'),
+      thingProperty: input.value('coverArtistContribs'),
+      artistProperty: input.value('trackCoverArtistContributions'),
+      date: '#trackArtDate',
+    }).outputs({
+      '#resolvedContribs': '#coverArtistContribs',
+    }),
+
+    exposeDependencyOrContinue({
+      dependency: '#coverArtistContribs',
+      mode: input.value('empty'),
+    }),
+
+    withPropertyFromAlbum({
+      property: input.value('trackCoverArtistContribs'),
+    }),
+
+    withRecontextualizedContributionList({
+      list: '#album.trackCoverArtistContribs',
+      artistProperty: input.value('trackCoverArtistContributions'),
+    }),
+
+    withRedatedContributionList({
+      list: '#album.trackCoverArtistContribs',
+      date: '#trackArtDate',
+    }),
+
+    {
+      dependencies: ['#album.trackCoverArtistContribs'],
+      compute: (continuation, {
+        ['#album.trackCoverArtistContribs']: coverArtistContribs,
+      }) => continuation({
+        ['#coverArtistContribs']: coverArtistContribs,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/track/withHasUniqueCoverArt.js b/src/data/composite/things/track/withHasUniqueCoverArt.js
index f7e65f25..85d3b92a 100644
--- a/src/data/composite/things/track/withHasUniqueCoverArt.js
+++ b/src/data/composite/things/track/withHasUniqueCoverArt.js
@@ -5,11 +5,18 @@
 // or a placeholder. (This property is named hasUniqueCoverArt instead of
 // the usual hasCoverArt to emphasize that it does not inherit from the
 // album.)
+//
+// withHasUniqueCoverArt is based only around the presence of *specified*
+// cover artist contributions, not whether the references to artists on those
+// contributions actually resolve to anything. It completely evades interacting
+// with find/replace.
 
 import {input, templateCompositeFrom} from '#composite';
-import {empty} from '#sugar';
 
-import {withResolvedContribs} from '#composite/wiki-data';
+import {raiseOutputWithoutDependency, withResultOfAvailabilityCheck}
+  from '#composite/control-flow';
+import {fillMissingListItems, withFlattenedList, withPropertyFromList}
+  from '#composite/data';
 
 import withPropertyFromAlbum from './withPropertyFromAlbum.js';
 
@@ -29,36 +36,73 @@ export default templateCompositeFrom({
           : continuation()),
     },
 
-    withResolvedContribs({
+    withResultOfAvailabilityCheck({
       from: 'coverArtistContribs',
-      date: input.value(null),
+      mode: input.value('empty'),
     }),
 
     {
-      dependencies: ['#resolvedContribs'],
+      dependencies: ['#availability'],
       compute: (continuation, {
-        ['#resolvedContribs']: contribsFromTrack,
+        ['#availability']: availability,
       }) =>
-        (empty(contribsFromTrack)
-          ? continuation()
-          : continuation.raiseOutput({
+        (availability
+          ? continuation.raiseOutput({
               ['#hasUniqueCoverArt']: true,
-            })),
+            })
+          : continuation()),
     },
 
     withPropertyFromAlbum({
       property: input.value('trackCoverArtistContribs'),
+      internal: input.value(true),
+    }),
+
+    withResultOfAvailabilityCheck({
+      from: '#album.trackCoverArtistContribs',
+      mode: input.value('empty'),
     }),
 
     {
-      dependencies: ['#album.trackCoverArtistContribs'],
+      dependencies: ['#availability'],
       compute: (continuation, {
-        ['#album.trackCoverArtistContribs']: contribsFromAlbum,
+        ['#availability']: availability,
       }) =>
-        continuation.raiseOutput({
-          ['#hasUniqueCoverArt']:
-            !empty(contribsFromAlbum),
-        }),
+        (availability
+          ? continuation.raiseOutput({
+              ['#hasUniqueCoverArt']: true,
+            })
+          : continuation()),
     },
+
+    raiseOutputWithoutDependency({
+      dependency: 'trackArtworks',
+      mode: input.value('empty'),
+      output: input.value({'#hasUniqueCoverArt': false}),
+    }),
+
+    withPropertyFromList({
+      list: 'trackArtworks',
+      property: input.value('artistContribs'),
+      internal: input.value(true),
+    }),
+
+    // Since we're getting the update value for each artwork's artistContribs,
+    // it may not be set at all, and in that case won't be exposing as [].
+    fillMissingListItems({
+      list: '#trackArtworks.artistContribs',
+      fill: input.value([]),
+    }),
+
+    withFlattenedList({
+      list: '#trackArtworks.artistContribs',
+    }),
+
+    withResultOfAvailabilityCheck({
+      from: '#flattenedList',
+      mode: input.value('empty'),
+    }).outputs({
+      '#availability': '#hasUniqueCoverArt',
+    }),
   ],
 });
diff --git a/src/data/composite/things/track/withOriginalRelease.js b/src/data/composite/things/track/withMainRelease.js
index c7f49657..3a91edae 100644
--- a/src/data/composite/things/track/withOriginalRelease.js
+++ b/src/data/composite/things/track/withMainRelease.js
@@ -1,62 +1,54 @@
-// Just includes the original release of this track as a dependency.
-// If this track isn't a rerelease, then it'll provide null, unless the
-// {selfIfOriginal} option is set, in which case it'll provide this track
-// itself. This will early exit (with notFoundValue) if the original release
+// Just includes the main release of this track as a dependency.
+// If this track isn't a secondary release, then it'll provide null, unless
+// the {selfIfMain} option is set, in which case it'll provide this track
+// itself. This will early exit (with notFoundValue) if the main release
 // is specified by reference and that reference doesn't resolve to anything.
 
 import {input, templateCompositeFrom} from '#composite';
-import find from '#find';
-import {validateWikiData} from '#validators';
 
 import {exitWithoutDependency, withResultOfAvailabilityCheck}
   from '#composite/control-flow';
 import {withResolvedReference} from '#composite/wiki-data';
+import {soupyFind} from '#composite/wiki-properties';
 
 export default templateCompositeFrom({
-  annotation: `withOriginalRelease`,
+  annotation: `withMainRelease`,
 
   inputs: {
-    selfIfOriginal: input({type: 'boolean', defaultValue: false}),
-
-    data: input({
-      validate: validateWikiData({referenceType: 'track'}),
-      defaultDependency: 'trackData',
-    }),
-
+    selfIfMain: input({type: 'boolean', defaultValue: false}),
     notFoundValue: input({defaultValue: null}),
   },
 
-  outputs: ['#originalRelease'],
+  outputs: ['#mainRelease'],
 
   steps: () => [
     withResultOfAvailabilityCheck({
-      from: 'originalReleaseTrack',
+      from: 'mainReleaseTrack',
     }),
 
     {
       dependencies: [
         input.myself(),
-        input('selfIfOriginal'),
+        input('selfIfMain'),
         '#availability',
       ],
 
       compute: (continuation, {
         [input.myself()]: track,
-        [input('selfIfOriginal')]: selfIfOriginal,
+        [input('selfIfMain')]: selfIfMain,
         '#availability': availability,
       }) =>
         (availability
           ? continuation()
           : continuation.raiseOutput({
-              ['#originalRelease']:
-                (selfIfOriginal ? track : null),
+              ['#mainRelease']:
+                (selfIfMain ? track : null),
             })),
     },
 
     withResolvedReference({
-      ref: 'originalReleaseTrack',
-      data: input('data'),
-      find: input.value(find.track),
+      ref: 'mainReleaseTrack',
+      find: soupyFind.input('track'),
     }),
 
     exitWithoutDependency({
@@ -71,7 +63,7 @@ export default templateCompositeFrom({
         ['#resolvedReference']: resolvedReference,
       }) =>
         continuation({
-          ['#originalRelease']: resolvedReference,
+          ['#mainRelease']: resolvedReference,
         }),
     },
   ],
diff --git a/src/data/composite/things/track/withOtherReleases.js b/src/data/composite/things/track/withOtherReleases.js
index f8c1c3f0..bb3e8983 100644
--- a/src/data/composite/things/track/withOtherReleases.js
+++ b/src/data/composite/things/track/withOtherReleases.js
@@ -1,8 +1,9 @@
-import {input, templateCompositeFrom} from '#composite';
+// Gets all releases of the current track *except* this track itself;
+// in other words, all other releases of the current track.
 
-import {exitWithoutDependency} from '#composite/control-flow';
+import {input, templateCompositeFrom} from '#composite';
 
-import withOriginalRelease from './withOriginalRelease.js';
+import withAllReleases from './withAllReleases.js';
 
 export default templateCompositeFrom({
   annotation: `withOtherReleases`,
@@ -10,31 +11,16 @@ export default templateCompositeFrom({
   outputs: ['#otherReleases'],
 
   steps: () => [
-    exitWithoutDependency({
-      dependency: 'trackData',
-      mode: input.value('empty'),
-    }),
-
-    withOriginalRelease({
-      selfIfOriginal: input.value(true),
-      notFoundValue: input.value([]),
-    }),
+    withAllReleases(),
 
     {
-      dependencies: [input.myself(), '#originalRelease', 'trackData'],
+      dependencies: [input.myself(), '#allReleases'],
       compute: (continuation, {
         [input.myself()]: thisTrack,
-        ['#originalRelease']: originalRelease,
-        trackData,
+        ['#allReleases']: allReleases,
       }) => continuation({
         ['#otherReleases']:
-          (originalRelease === thisTrack
-            ? []
-            : [originalRelease])
-            .concat(trackData.filter(track =>
-              track !== originalRelease &&
-              track !== thisTrack &&
-              track.originalReleaseTrack === originalRelease)),
+          allReleases.filter(track => track !== thisTrack),
       }),
     },
   ],
diff --git a/src/data/composite/things/track/withPropertyFromAlbum.js b/src/data/composite/things/track/withPropertyFromAlbum.js
index d41390fa..a203c2e7 100644
--- a/src/data/composite/things/track/withPropertyFromAlbum.js
+++ b/src/data/composite/things/track/withPropertyFromAlbum.js
@@ -2,17 +2,15 @@
 // property name prefixed with '#album.' (by default).
 
 import {input, templateCompositeFrom} from '#composite';
-import {is} from '#validators';
 
 import {withPropertyFromObject} from '#composite/data';
 
-import withAlbum from './withAlbum.js';
-
 export default templateCompositeFrom({
   annotation: `withPropertyFromAlbum`,
 
   inputs: {
     property: input.staticValue({type: 'string'}),
+    internal: input({type: 'boolean', defaultValue: false}),
   },
 
   outputs: ({
@@ -20,11 +18,21 @@ export default templateCompositeFrom({
   }) => ['#album.' + property],
 
   steps: () => [
-    withAlbum(),
+    // XXX: This is a ridiculous hack considering `defaultValue` above.
+    // If we were certain what was up, we'd just get around to fixing it LOL
+    {
+      dependencies: [input('internal')],
+      compute: (continuation, {
+        [input('internal')]: internal,
+      }) => continuation({
+        ['#internal']: internal ?? false,
+      }),
+    },
 
     withPropertyFromObject({
-      object: '#album',
+      object: 'album',
       property: input('property'),
+      internal: '#internal',
     }),
 
     {
diff --git a/src/data/composite/things/track/withPropertyFromOriginalRelease.js b/src/data/composite/things/track/withPropertyFromMainRelease.js
index fd37f6de..393a4c63 100644
--- a/src/data/composite/things/track/withPropertyFromOriginalRelease.js
+++ b/src/data/composite/things/track/withPropertyFromMainRelease.js
@@ -1,8 +1,8 @@
-// Provides a value inherited from the original release, if applicable, and a
-// flag indicating if this track is a rerelase or not.
+// Provides a value inherited from the main release, if applicable, and a
+// flag indicating if this track is a secondary release or not.
 //
-// Like withOriginalRelease, this will early exit (with notFoundValue) if the
-// original release is specified by reference and that reference doesn't
+// Like withMainRelease, this will early exit (with notFoundValue) if the
+// main release is specified by reference and that reference doesn't
 // resolve to anything.
 
 import {input, templateCompositeFrom} from '#composite';
@@ -10,10 +10,10 @@ import {input, templateCompositeFrom} from '#composite';
 import {withResultOfAvailabilityCheck} from '#composite/control-flow';
 import {withPropertyFromObject} from '#composite/data';
 
-import withOriginalRelease from './withOriginalRelease.js';
+import withMainRelease from './withMainRelease.js';
 
 export default templateCompositeFrom({
-  annotation: `inheritFromOriginalRelease`,
+  annotation: `inheritFromMainRelease`,
 
   inputs: {
     property: input({type: 'string'}),
@@ -26,18 +26,18 @@ export default templateCompositeFrom({
   outputs: ({
     [input.staticValue('property')]: property,
   }) =>
-    ['#isRerelease'].concat(
+    ['#isSecondaryRelease'].concat(
       (property
-        ? ['#original.' + property]
-        : ['#originalValue'])),
+        ? ['#mainRelease.' + property]
+        : ['#mainReleaseValue'])),
 
   steps: () => [
-    withOriginalRelease({
+    withMainRelease({
       notFoundValue: input('notFoundValue'),
     }),
 
     withResultOfAvailabilityCheck({
-      from: '#originalRelease',
+      from: '#mainRelease',
     }),
 
     {
@@ -54,14 +54,14 @@ export default templateCompositeFrom({
           ? continuation()
           : continuation.raiseOutput(
               Object.assign(
-                {'#isRerelease': false},
+                {'#isSecondaryRelease': false},
                 (property
-                  ? {['#original.' + property]: null}
-                  : {'#originalValue': null})))),
+                  ? {['#mainRelease.' + property]: null}
+                  : {'#mainReleaseValue': null})))),
     },
 
     withPropertyFromObject({
-      object: '#originalRelease',
+      object: '#mainRelease',
       property: input('property'),
     }),
 
@@ -77,10 +77,10 @@ export default templateCompositeFrom({
       }) =>
         continuation.raiseOutput(
           Object.assign(
-            {'#isRerelease': true},
+            {'#isSecondaryRelease': true},
             (property
-              ? {['#original.' + property]: value}
-              : {'#originalValue': value}))),
+              ? {['#mainRelease.' + property]: value}
+              : {'#mainReleaseValue': value}))),
     },
   ],
 });
diff --git a/src/data/composite/things/track/withTrackArtDate.js b/src/data/composite/things/track/withTrackArtDate.js
index e2c4d8bc..9b7b61c7 100644
--- a/src/data/composite/things/track/withTrackArtDate.js
+++ b/src/data/composite/things/track/withTrackArtDate.js
@@ -1,11 +1,3 @@
-// Gets the date of cover art release. This represents only the track's own
-// unique cover artwork, if any.
-//
-// If the 'fallback' option is false (the default), this will only output
-// the track's own coverArtDate or its album's trackArtDate. If 'fallback'
-// is set, and neither of these is available, it'll output the track's own
-// date instead.
-
 import {input, templateCompositeFrom} from '#composite';
 import {isDate} from '#validators';
 
@@ -24,11 +16,6 @@ export default templateCompositeFrom({
       defaultDependency: 'coverArtDate',
       acceptsNull: true,
     }),
-
-    fallback: input({
-      type: 'boolean',
-      defaultValue: false,
-    }),
   },
 
   outputs: ['#trackArtDate'],
@@ -57,20 +44,13 @@ export default templateCompositeFrom({
     }),
 
     {
-      dependencies: [
-        '#album.trackArtDate',
-        input('fallback'),
-      ],
-
+      dependencies: ['#album.trackArtDate'],
       compute: (continuation, {
         ['#album.trackArtDate']: albumTrackArtDate,
-        [input('fallback')]: fallback,
       }) =>
         (albumTrackArtDate
           ? continuation.raiseOutput({'#trackArtDate': albumTrackArtDate})
-       : fallback
-          ? continuation()
-          : continuation.raiseOutput({'#trackArtDate': null})),
+          : continuation()),
     },
 
     withDate().outputs({
diff --git a/src/data/composite/things/track/withTrackNumber.js b/src/data/composite/things/track/withTrackNumber.js
new file mode 100644
index 00000000..61428e8c
--- /dev/null
+++ b/src/data/composite/things/track/withTrackNumber.js
@@ -0,0 +1,50 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withIndexInList, withPropertiesFromObject} from '#composite/data';
+
+import withContainingTrackSection from './withContainingTrackSection.js';
+
+export default templateCompositeFrom({
+  annotation: `withTrackNumber`,
+
+  outputs: ['#trackNumber'],
+
+  steps: () => [
+    withContainingTrackSection(),
+
+    // Zero is the fallback, not one, but in most albums the first track
+    // (and its intended output by this composition) will be one.
+    raiseOutputWithoutDependency({
+      dependency: '#trackSection',
+      output: input.value({'#trackNumber': 0}),
+    }),
+
+    withPropertiesFromObject({
+      object: '#trackSection',
+      properties: input.value(['tracks', 'startCountingFrom']),
+    }),
+
+    withIndexInList({
+      list: '#trackSection.tracks',
+      item: input.myself(),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#index',
+      output: input.value({'#trackNumber': 0}),
+    }),
+
+    {
+      dependencies: ['#trackSection.startCountingFrom', '#index'],
+      compute: (continuation, {
+        ['#trackSection.startCountingFrom']: startCountingFrom,
+        ['#index']: index,
+      }) => continuation({
+        ['#trackNumber']:
+          startCountingFrom +
+          index,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/gobbleSoupyFind.js b/src/data/composite/wiki-data/gobbleSoupyFind.js
new file mode 100644
index 00000000..aec3f5b1
--- /dev/null
+++ b/src/data/composite/wiki-data/gobbleSoupyFind.js
@@ -0,0 +1,39 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {withPropertyFromObject} from '#composite/data';
+
+import inputSoupyFind, {getSoupyFindInputKey} from './inputSoupyFind.js';
+
+export default templateCompositeFrom({
+  annotation: `gobbleSoupyFind`,
+
+  inputs: {
+    find: inputSoupyFind(),
+  },
+
+  outputs: ['#find'],
+
+  steps: () => [
+    {
+      dependencies: [input('find')],
+      compute: (continuation, {
+        [input('find')]: find,
+      }) =>
+        (typeof find === 'function'
+          ? continuation.raiseOutput({
+              ['#find']: find,
+            })
+          : continuation({
+              ['#key']:
+                getSoupyFindInputKey(find),
+            })),
+    },
+
+    withPropertyFromObject({
+      object: 'find',
+      property: '#key',
+    }).outputs({
+      '#value': '#find',
+    }),
+  ],
+});
diff --git a/src/data/composite/wiki-data/gobbleSoupyReverse.js b/src/data/composite/wiki-data/gobbleSoupyReverse.js
new file mode 100644
index 00000000..86a1061c
--- /dev/null
+++ b/src/data/composite/wiki-data/gobbleSoupyReverse.js
@@ -0,0 +1,39 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {withPropertyFromObject} from '#composite/data';
+
+import inputSoupyReverse, {getSoupyReverseInputKey} from './inputSoupyReverse.js';
+
+export default templateCompositeFrom({
+  annotation: `gobbleSoupyReverse`,
+
+  inputs: {
+    reverse: inputSoupyReverse(),
+  },
+
+  outputs: ['#reverse'],
+
+  steps: () => [
+    {
+      dependencies: [input('reverse')],
+      compute: (continuation, {
+        [input('reverse')]: reverse,
+      }) =>
+        (typeof reverse === 'function'
+          ? continuation.raiseOutput({
+              ['#reverse']: reverse,
+            })
+          : continuation({
+              ['#key']:
+                getSoupyReverseInputKey(reverse),
+            })),
+    },
+
+    withPropertyFromObject({
+      object: 'reverse',
+      property: '#key',
+    }).outputs({
+      '#value': '#reverse',
+    }),
+  ],
+});
diff --git a/src/data/composite/wiki-data/helpers/withResolvedReverse.js b/src/data/composite/wiki-data/helpers/withResolvedReverse.js
new file mode 100644
index 00000000..818f60b7
--- /dev/null
+++ b/src/data/composite/wiki-data/helpers/withResolvedReverse.js
@@ -0,0 +1,40 @@
+// Actually execute a reverse function.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import inputWikiData from '../inputWikiData.js';
+
+export default templateCompositeFrom({
+  annotation: `withReverseReferenceList`,
+
+  inputs: {
+    data: inputWikiData({allowMixedTypes: true}),
+    reverse: input({type: 'function'}),
+    options: input({type: 'object', defaultValue: null}),
+  },
+
+  outputs: ['#resolvedReverse'],
+
+  steps: () => [
+    {
+      dependencies: [
+        input.myself(),
+        input('data'),
+        input('reverse'),
+        input('options'),
+      ],
+
+      compute: (continuation, {
+        [input.myself()]: myself,
+        [input('data')]: data,
+        [input('reverse')]: reverseFunction,
+        [input('options')]: opts,
+      }) => continuation({
+        ['#resolvedReverse']:
+          (data
+            ? reverseFunction(myself, data, opts)
+            : reverseFunction(myself, opts)),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/helpers/withReverseList-template.js b/src/data/composite/wiki-data/helpers/withReverseList-template.js
deleted file mode 100644
index 6ffd5d70..00000000
--- a/src/data/composite/wiki-data/helpers/withReverseList-template.js
+++ /dev/null
@@ -1,193 +0,0 @@
-// Baseline implementation shared by or underlying reverse lists.
-//
-// This is a very rudimentary "these compositions have basically the same
-// shape but slightly different guts midway through" kind of solution,
-// and should use compositional subroutines instead, once those are ready.
-//
-// But, until then, this has the same effect of avoiding code duplication
-// and clearly identifying differences.
-//
-// ---
-//
-// This implementation uses a global cache (via WeakMap) to attempt to speed
-// up subsequent similar accesses.
-//
-// This has absolutely not been rigorously tested with altering properties of
-// data objects in a wiki data array which is reused. If a new wiki data array
-// is used, a fresh cache will always be created.
-//
-
-import {input, templateCompositeFrom} from '#composite';
-import {sortByDate} from '#sort';
-import {stitchArrays} from '#sugar';
-
-import {exitWithoutDependency, raiseOutputWithoutDependency}
-  from '#composite/control-flow';
-import {withFlattenedList, withMappedList} from '#composite/data';
-
-import inputWikiData from '../inputWikiData.js';
-
-export default function withReverseList_template({
-  annotation,
-
-  propertyInputName,
-  outputName,
-
-  additionalInputs = {},
-
-  customCompositionSteps,
-}) {
-  // Mapping of reference list property to WeakMap.
-  // Each WeakMap maps a wiki data array to another weak map,
-  // which in turn maps each referenced thing to an array of
-  // things referencing it.
-  const caches = new Map();
-
-  return templateCompositeFrom({
-    annotation,
-
-    inputs: {
-      data: inputWikiData({
-        allowMixedTypes: true,
-      }),
-
-      [propertyInputName]: input({
-        type: 'string',
-      }),
-
-      ...additionalInputs,
-    },
-
-    outputs: [outputName],
-
-    steps: () => [
-      // Early exit with an empty array if the data list isn't available.
-      exitWithoutDependency({
-        dependency: input('data'),
-        value: input.value([]),
-      }),
-
-      // Raise an empty array (don't early exit) if the data list is empty.
-      raiseOutputWithoutDependency({
-        dependency: input('data'),
-        mode: input.value('empty'),
-        output: input.value({[outputName]: []}),
-      }),
-
-      // Check for an existing cache record which corresponds to this
-      // property input and input('data'). If it exists, query it for the
-      // current thing, and raise that; if it doesn't, create it, put it
-      // where it needs to be, and provide it so the next steps can fill
-      // it in.
-      {
-        dependencies: [input(propertyInputName), input('data'), input.myself()],
-
-        compute: (continuation, {
-          [input(propertyInputName)]: property,
-          [input('data')]: data,
-          [input.myself()]: myself,
-        }) => {
-          if (!caches.has(property)) {
-            const cache = new WeakMap();
-            caches.set(property, cache);
-
-            const cacheRecord = new WeakMap();
-            cache.set(data, cacheRecord);
-
-            return continuation({
-              ['#cacheRecord']: cacheRecord,
-            });
-          }
-
-          const cache = caches.get(property);
-
-          if (!cache.has(data)) {
-            const cacheRecord = new WeakMap();
-            cache.set(data, cacheRecord);
-
-            return continuation({
-              ['#cacheRecord']: cacheRecord,
-            });
-          }
-
-          return continuation.raiseOutput({
-            [outputName]:
-              cache.get(data).get(myself) ?? [],
-          });
-        },
-      },
-
-      ...customCompositionSteps(),
-
-      // Actually fill in the cache record. Since we're building up a *reverse*
-      // reference list, track connections in terms of the referenced thing.
-      // Although we gather all referenced things into a set and provide that
-      // for sorting purposes in the next step, we *don't* reprovide the cache
-      // record, because we're mutating that in-place - we'll just reuse its
-      // existing '#cacheRecord' dependency.
-      {
-        dependencies: ['#cacheRecord', '#referencingThings', '#referencedThings'],
-        compute: (continuation, {
-          ['#cacheRecord']: cacheRecord,
-          ['#referencingThings']: referencingThings,
-          ['#referencedThings']: referencedThings,
-        }) => {
-          const allReferencedThings = new Set();
-
-          stitchArrays({
-            referencingThing: referencingThings,
-            referencedThings: referencedThings,
-          }).forEach(({referencingThing, referencedThings}) => {
-              for (const referencedThing of referencedThings) {
-                if (cacheRecord.has(referencedThing)) {
-                  cacheRecord.get(referencedThing).push(referencingThing);
-                } else {
-                  cacheRecord.set(referencedThing, [referencingThing]);
-                  allReferencedThings.add(referencedThing);
-                }
-              }
-            });
-
-          return continuation({
-            ['#allReferencedThings']:
-              allReferencedThings,
-          });
-        },
-      },
-
-      // Sort the entries in the cache records, too, just by date - the rest of
-      // sorting should be handled outside of this composition, either preceding
-      // (changing the 'data' input) or following (sorting the output).
-      // Again we're mutating in place, so no need to reprovide '#cacheRecord'
-      // here.
-      {
-        dependencies: ['#cacheRecord', '#allReferencedThings'],
-        compute: (continuation, {
-          ['#cacheRecord']: cacheRecord,
-          ['#allReferencedThings']: allReferencedThings,
-        }) => {
-          for (const referencedThing of allReferencedThings) {
-            if (cacheRecord.has(referencedThing)) {
-              const referencingThings = cacheRecord.get(referencedThing);
-              sortByDate(referencingThings);
-            }
-          }
-
-          return continuation();
-        },
-      },
-
-      // Then just pluck out the current object from the now-filled cache record!
-      {
-        dependencies: ['#cacheRecord', input.myself()],
-        compute: (continuation, {
-          ['#cacheRecord']: cacheRecord,
-          [input.myself()]: myself,
-        }) => continuation({
-          [outputName]:
-            cacheRecord.get(myself) ?? [],
-        }),
-      },
-    ],
-  });
-}
diff --git a/src/data/composite/wiki-data/index.js b/src/data/composite/wiki-data/index.js
index 51d07384..38afc2ac 100644
--- a/src/data/composite/wiki-data/index.js
+++ b/src/data/composite/wiki-data/index.js
@@ -5,23 +5,25 @@
 //
 
 export {default as exitWithoutContribs} from './exitWithoutContribs.js';
+export {default as gobbleSoupyFind} from './gobbleSoupyFind.js';
+export {default as gobbleSoupyReverse} from './gobbleSoupyReverse.js';
 export {default as inputNotFoundMode} from './inputNotFoundMode.js';
+export {default as inputSoupyFind} from './inputSoupyFind.js';
+export {default as inputSoupyReverse} from './inputSoupyReverse.js';
 export {default as inputWikiData} from './inputWikiData.js';
+export {default as splitContentNodesAround} from './splitContentNodesAround.js';
 export {default as withClonedThings} from './withClonedThings.js';
+export {default as withConstitutedArtwork} from './withConstitutedArtwork.js';
+export {default as withContentNodes} from './withContentNodes.js';
 export {default as withContributionListSums} from './withContributionListSums.js';
 export {default as withCoverArtDate} from './withCoverArtDate.js';
 export {default as withDirectory} from './withDirectory.js';
-export {default as withParsedCommentaryEntries} from './withParsedCommentaryEntries.js';
 export {default as withRecontextualizedContributionList} from './withRecontextualizedContributionList.js';
 export {default as withRedatedContributionList} from './withRedatedContributionList.js';
 export {default as withResolvedAnnotatedReferenceList} from './withResolvedAnnotatedReferenceList.js';
 export {default as withResolvedContribs} from './withResolvedContribs.js';
 export {default as withResolvedReference} from './withResolvedReference.js';
 export {default as withResolvedReferenceList} from './withResolvedReferenceList.js';
-export {default as withResolvedSeriesList} from './withResolvedSeriesList.js';
-export {default as withReverseAnnotatedReferenceList} from './withReverseAnnotatedReferenceList.js';
-export {default as withReverseContributionList} from './withReverseContributionList.js';
 export {default as withReverseReferenceList} from './withReverseReferenceList.js';
-export {default as withReverseSingleReferenceList} from './withReverseSingleReferenceList.js';
 export {default as withThingsSortedAlphabetically} from './withThingsSortedAlphabetically.js';
 export {default as withUniqueReferencingThing} from './withUniqueReferencingThing.js';
diff --git a/src/data/composite/wiki-data/inputSoupyFind.js b/src/data/composite/wiki-data/inputSoupyFind.js
new file mode 100644
index 00000000..020f4990
--- /dev/null
+++ b/src/data/composite/wiki-data/inputSoupyFind.js
@@ -0,0 +1,28 @@
+import {input} from '#composite';
+import {anyOf, isFunction, isString} from '#validators';
+
+function inputSoupyFind() {
+  return input({
+    validate:
+      anyOf(
+        isFunction,
+        val => {
+          isString(val);
+
+          if (!val.startsWith('_soupyFind:')) {
+            throw new Error(`Expected soupyFind.input() token`);
+          }
+
+          return true;
+        }),
+  });
+}
+
+inputSoupyFind.input = key =>
+  input.value('_soupyFind:' + key);
+
+export default inputSoupyFind;
+
+export function getSoupyFindInputKey(value) {
+  return value.slice('_soupyFind:'.length);
+}
diff --git a/src/data/composite/wiki-data/inputSoupyReverse.js b/src/data/composite/wiki-data/inputSoupyReverse.js
new file mode 100644
index 00000000..0b0a23fe
--- /dev/null
+++ b/src/data/composite/wiki-data/inputSoupyReverse.js
@@ -0,0 +1,32 @@
+import {input} from '#composite';
+import {anyOf, isFunction, isString} from '#validators';
+
+function inputSoupyReverse() {
+  return input({
+    validate:
+      anyOf(
+        isFunction,
+        val => {
+          isString(val);
+
+          if (!val.startsWith('_soupyReverse:')) {
+            throw new Error(`Expected soupyReverse.input() token`);
+          }
+
+          return true;
+        }),
+  });
+}
+
+inputSoupyReverse.input = key =>
+  input.value('_soupyReverse:' + key);
+
+export default inputSoupyReverse;
+
+export function getSoupyReverseInputKey(value) {
+  return value.slice('_soupyReverse:'.length).replace(/\.unique$/, '');
+}
+
+export function doesSoupyReverseInputWantUnique(value) {
+  return value.endsWith('.unique');
+}
diff --git a/src/data/composite/wiki-data/inputWikiData.js b/src/data/composite/wiki-data/inputWikiData.js
index cf7a7c2c..b9021986 100644
--- a/src/data/composite/wiki-data/inputWikiData.js
+++ b/src/data/composite/wiki-data/inputWikiData.js
@@ -12,6 +12,6 @@ export default function inputWikiData({
 } = {}) {
   return input({
     validate: validateWikiData({referenceType, allowMixedTypes}),
-    acceptsNull: true,
+    defaultValue: null,
   });
 }
diff --git a/src/data/composite/wiki-data/splitContentNodesAround.js b/src/data/composite/wiki-data/splitContentNodesAround.js
new file mode 100644
index 00000000..6648d8e1
--- /dev/null
+++ b/src/data/composite/wiki-data/splitContentNodesAround.js
@@ -0,0 +1,87 @@
+import {input, templateCompositeFrom} from '#composite';
+import {splitContentNodesAround} from '#replacer';
+import {anyOf, isFunction, validateInstanceOf} from '#validators';
+
+import {withFilteredList, withMappedList, withUnflattenedList}
+  from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: `splitContentNodesAround`,
+
+  inputs: {
+    nodes: input({type: 'array'}),
+
+    around: input({
+      validate:
+        anyOf(isFunction, validateInstanceOf(RegExp)),
+    }),
+  },
+
+  outputs: ['#contentNodeLists'],
+
+  steps: () => [
+    {
+      dependencies: [input('nodes'), input('around')],
+
+      compute: (continuation, {
+        [input('nodes')]: nodes,
+        [input('around')]: splitter,
+      }) => continuation({
+        ['#nodes']:
+          Array.from(splitContentNodesAround(nodes, splitter)),
+      }),
+    },
+
+    withMappedList({
+      list: '#nodes',
+      map: input.value(node => node.type === 'separator'),
+    }).outputs({
+      '#mappedList': '#separatorFilter',
+    }),
+
+    withMappedList({
+      list: '#separatorFilter',
+      filter: '#separatorFilter',
+      map: input.value((_node, index) => index),
+    }),
+
+    withFilteredList({
+      list: '#mappedList',
+      filter: '#separatorFilter',
+    }).outputs({
+      '#filteredList': '#separatorIndices',
+    }),
+
+    {
+      dependencies: ['#nodes', '#separatorFilter'],
+
+      compute: (continuation, {
+        ['#nodes']: nodes,
+        ['#separatorFilter']: separatorFilter,
+      }) => continuation({
+        ['#nodes']:
+          nodes.map((node, index) =>
+            (separatorFilter[index]
+              ? null
+              : node)),
+      }),
+    },
+
+    {
+      dependencies: ['#separatorIndices'],
+      compute: (continuation, {
+        ['#separatorIndices']: separatorIndices,
+      }) => continuation({
+        ['#unflattenIndices']:
+          [0, ...separatorIndices],
+      }),
+    },
+
+    withUnflattenedList({
+      list: '#nodes',
+      indices: '#unflattenIndices',
+    }).outputs({
+      '#unflattenedList': '#contentNodeLists',
+    }),
+  ],
+});
diff --git a/src/data/composite/wiki-data/withConstitutedArtwork.js b/src/data/composite/wiki-data/withConstitutedArtwork.js
new file mode 100644
index 00000000..28d719e2
--- /dev/null
+++ b/src/data/composite/wiki-data/withConstitutedArtwork.js
@@ -0,0 +1,60 @@
+import {input, templateCompositeFrom} from '#composite';
+import thingConstructors from '#things';
+
+export default templateCompositeFrom({
+  annotation: `withConstitutedArtwork`,
+
+  inputs: {
+    thingProperty: input({type: 'string', acceptsNull: true}),
+    dimensionsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    fileExtensionFromThingProperty: input({type: 'string', acceptsNull: true}),
+    dateFromThingProperty: input({type: 'string', acceptsNull: true}),
+    artistContribsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    artistContribsArtistProperty: input({type: 'string', acceptsNull: true}),
+    artTagsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    referencedArtworksFromThingProperty: input({type: 'string', acceptsNull: true}),
+  },
+
+  outputs: ['#constitutedArtwork'],
+
+  steps: () => [
+    {
+      dependencies: [
+        input.myself(),
+        input('thingProperty'),
+        input('dimensionsFromThingProperty'),
+        input('fileExtensionFromThingProperty'),
+        input('dateFromThingProperty'),
+        input('artistContribsFromThingProperty'),
+        input('artistContribsArtistProperty'),
+        input('artTagsFromThingProperty'),
+        input('referencedArtworksFromThingProperty'),
+      ],
+
+      compute: (continuation, {
+        [input.myself()]: myself,
+        [input('thingProperty')]: thingProperty,
+        [input('dimensionsFromThingProperty')]: dimensionsFromThingProperty,
+        [input('fileExtensionFromThingProperty')]: fileExtensionFromThingProperty,
+        [input('dateFromThingProperty')]: dateFromThingProperty,
+        [input('artistContribsFromThingProperty')]: artistContribsFromThingProperty,
+        [input('artistContribsArtistProperty')]: artistContribsArtistProperty,
+        [input('artTagsFromThingProperty')]: artTagsFromThingProperty,
+        [input('referencedArtworksFromThingProperty')]: referencedArtworksFromThingProperty,
+      }) => continuation({
+        ['#constitutedArtwork']:
+          Object.assign(new thingConstructors.Artwork, {
+            thing: myself,
+            thingProperty,
+            dimensionsFromThingProperty,
+            fileExtensionFromThingProperty,
+            artistContribsFromThingProperty,
+            artistContribsArtistProperty,
+            artTagsFromThingProperty,
+            dateFromThingProperty,
+            referencedArtworksFromThingProperty,
+          }),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/withContentNodes.js b/src/data/composite/wiki-data/withContentNodes.js
new file mode 100644
index 00000000..d014d43b
--- /dev/null
+++ b/src/data/composite/wiki-data/withContentNodes.js
@@ -0,0 +1,25 @@
+import {input, templateCompositeFrom} from '#composite';
+import {parseContentNodes} from '#replacer';
+
+export default templateCompositeFrom({
+  annotation: `withContentNodes`,
+
+  inputs: {
+    from: input({type: 'string', acceptsNull: false}),
+  },
+
+  outputs: ['#contentNodes'],
+
+  steps: () => [
+    {
+      dependencies: [input('from')],
+
+      compute: (continuation, {
+        [input('from')]: string,
+      }) => continuation({
+        ['#contentNodes']:
+          parseContentNodes(string),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/withCoverArtDate.js b/src/data/composite/wiki-data/withCoverArtDate.js
index 0c644c77..a114d5ff 100644
--- a/src/data/composite/wiki-data/withCoverArtDate.js
+++ b/src/data/composite/wiki-data/withCoverArtDate.js
@@ -1,7 +1,3 @@
-// Gets the current thing's coverArtDate, or, if the 'fallback' option is set,
-// the thing's date. This is always null if the thing doesn't actually have
-// any coverArtistContribs.
-
 import {input, templateCompositeFrom} from '#composite';
 import {isDate} from '#validators';
 
@@ -18,11 +14,6 @@ export default templateCompositeFrom({
       defaultDependency: 'coverArtDate',
       acceptsNull: true,
     }),
-
-    fallback: input({
-      type: 'boolean',
-      defaultValue: false,
-    }),
   },
 
   outputs: ['#coverArtDate'],
@@ -50,21 +41,11 @@ export default templateCompositeFrom({
     },
 
     {
-      dependencies: [input('fallback')],
-      compute: (continuation, {
-        [input('fallback')]: fallback,
-      }) =>
-        (fallback
-          ? continuation()
-          : continuation.raiseOutput({'#coverArtDate': null})),
-    },
-
-    {
       dependencies: ['date'],
       compute: (continuation, {date}) =>
         (date
-          ? continuation.raiseOutput({'#coverArtDate': date})
-          : continuation.raiseOutput({'#coverArtDate': null})),
+          ? continuation({'#coverArtDate': date})
+          : continuation({'#coverArtDate': null})),
     },
   ],
 });
diff --git a/src/data/composite/wiki-data/withParsedCommentaryEntries.js b/src/data/composite/wiki-data/withParsedCommentaryEntries.js
deleted file mode 100644
index 144781a8..00000000
--- a/src/data/composite/wiki-data/withParsedCommentaryEntries.js
+++ /dev/null
@@ -1,261 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-import find from '#find';
-import {stitchArrays} from '#sugar';
-import {isCommentary} from '#validators';
-import {commentaryRegexCaseSensitive} from '#wiki-data';
-
-import {
-  fillMissingListItems,
-  withFlattenedList,
-  withPropertiesFromList,
-  withUnflattenedList,
-} from '#composite/data';
-
-import withResolvedReferenceList from './withResolvedReferenceList.js';
-
-export default templateCompositeFrom({
-  annotation: `withParsedCommentaryEntries`,
-
-  inputs: {
-    from: input({validate: isCommentary}),
-  },
-
-  outputs: ['#parsedCommentaryEntries'],
-
-  steps: () => [
-    {
-      dependencies: [input('from')],
-
-      compute: (continuation, {
-        [input('from')]: commentaryText,
-      }) => continuation({
-        ['#rawMatches']:
-          Array.from(commentaryText.matchAll(commentaryRegexCaseSensitive)),
-      }),
-    },
-
-    withPropertiesFromList({
-      list: '#rawMatches',
-      properties: input.value([
-        '0', // The entire match as a string.
-        'groups',
-        'index',
-      ]),
-    }).outputs({
-      '#rawMatches.0': '#rawMatches.text',
-      '#rawMatches.groups': '#rawMatches.groups',
-      '#rawMatches.index': '#rawMatches.startIndex',
-    }),
-
-    {
-      dependencies: [
-        '#rawMatches.text',
-        '#rawMatches.startIndex',
-      ],
-
-      compute: (continuation, {
-        ['#rawMatches.text']: text,
-        ['#rawMatches.startIndex']: startIndex,
-      }) => continuation({
-        ['#rawMatches.endIndex']:
-          stitchArrays({text, startIndex})
-            .map(({text, startIndex}) => startIndex + text.length),
-      }),
-    },
-
-    {
-      dependencies: [
-        input('from'),
-        '#rawMatches.startIndex',
-        '#rawMatches.endIndex',
-      ],
-
-      compute: (continuation, {
-        [input('from')]: commentaryText,
-        ['#rawMatches.startIndex']: startIndex,
-        ['#rawMatches.endIndex']: endIndex,
-      }) => continuation({
-        ['#entries.body']:
-          stitchArrays({startIndex, endIndex})
-            .map(({endIndex}, index, stitched) =>
-              (index === stitched.length - 1
-                ? commentaryText.slice(endIndex)
-                : commentaryText.slice(
-                    endIndex,
-                    stitched[index + 1].startIndex)))
-            .map(body => body.trim()),
-      }),
-    },
-
-    withPropertiesFromList({
-      list: '#rawMatches.groups',
-      prefix: input.value('#entries'),
-      properties: input.value([
-        'artistReferences',
-        'artistDisplayText',
-        'annotation',
-        'date',
-        'secondDate',
-        'dateKind',
-        'accessDate',
-        'accessKind',
-      ]),
-    }),
-
-    // The artistReferences group will always have a value, since it's required
-    // for the line to match in the first place.
-
-    {
-      dependencies: ['#entries.artistReferences'],
-      compute: (continuation, {
-        ['#entries.artistReferences']: artistReferenceTexts,
-      }) => continuation({
-        ['#entries.artistReferences']:
-          artistReferenceTexts
-            .map(text => text.split(',').map(ref => ref.trim())),
-      }),
-    },
-
-    withFlattenedList({
-      list: '#entries.artistReferences',
-    }),
-
-    withResolvedReferenceList({
-      list: '#flattenedList',
-      data: 'artistData',
-      find: input.value(find.artist),
-      notFoundMode: input.value('null'),
-    }),
-
-    withUnflattenedList({
-      list: '#resolvedReferenceList',
-    }).outputs({
-      '#unflattenedList': '#entries.artists',
-    }),
-
-    fillMissingListItems({
-      list: '#entries.artistDisplayText',
-      fill: input.value(null),
-    }),
-
-    fillMissingListItems({
-      list: '#entries.annotation',
-      fill: input.value(null),
-    }),
-
-    {
-      dependencies: ['#entries.annotation'],
-      compute: (continuation, {
-        ['#entries.annotation']: annotation,
-      }) => continuation({
-        ['#entries.webArchiveDate']:
-          annotation
-            .map(text => text?.match(/https?:\/\/web.archive.org\/web\/([0-9]{8,8})[0-9]*\//))
-            .map(match => match?.[1])
-            .map(dateText =>
-              (dateText
-                ? dateText.slice(0, 4) + '/' +
-                  dateText.slice(4, 6) + '/' +
-                  dateText.slice(6, 8)
-                : null)),
-      }),
-    },
-
-    {
-      dependencies: ['#entries.date'],
-      compute: (continuation, {
-        ['#entries.date']: date,
-      }) => continuation({
-        ['#entries.date']:
-          date
-            .map(date => date ? new Date(date) : null),
-      }),
-    },
-
-    {
-      dependencies: ['#entries.secondDate'],
-      compute: (continuation, {
-        ['#entries.secondDate']: secondDate,
-      }) => continuation({
-        ['#entries.secondDate']:
-          secondDate
-            .map(date => date ? new Date(date) : null),
-      }),
-    },
-
-    fillMissingListItems({
-      list: '#entries.dateKind',
-      fill: input.value(null),
-    }),
-
-    {
-      dependencies: ['#entries.accessDate', '#entries.webArchiveDate'],
-      compute: (continuation, {
-        ['#entries.accessDate']: accessDate,
-        ['#entries.webArchiveDate']: webArchiveDate,
-      }) => continuation({
-        ['#entries.accessDate']:
-          stitchArrays({accessDate, webArchiveDate})
-            .map(({accessDate, webArchiveDate}) =>
-              accessDate ??
-              webArchiveDate ??
-              null)
-            .map(date => date ? new Date(date) : date),
-      }),
-    },
-
-    {
-      dependencies: ['#entries.accessKind', '#entries.webArchiveDate'],
-      compute: (continuation, {
-        ['#entries.accessKind']: accessKind,
-        ['#entries.webArchiveDate']: webArchiveDate,
-      }) => continuation({
-        ['#entries.accessKind']:
-          stitchArrays({accessKind, webArchiveDate})
-            .map(({accessKind, webArchiveDate}) =>
-              accessKind ??
-              (webArchiveDate && 'captured') ??
-              null),
-      }),
-    },
-
-    {
-      dependencies: [
-        '#entries.artists',
-        '#entries.artistDisplayText',
-        '#entries.annotation',
-        '#entries.date',
-        '#entries.secondDate',
-        '#entries.dateKind',
-        '#entries.accessDate',
-        '#entries.accessKind',
-        '#entries.body',
-      ],
-
-      compute: (continuation, {
-        ['#entries.artists']: artists,
-        ['#entries.artistDisplayText']: artistDisplayText,
-        ['#entries.annotation']: annotation,
-        ['#entries.date']: date,
-        ['#entries.secondDate']: secondDate,
-        ['#entries.dateKind']: dateKind,
-        ['#entries.accessDate']: accessDate,
-        ['#entries.accessKind']: accessKind,
-        ['#entries.body']: body,
-      }) => continuation({
-        ['#parsedCommentaryEntries']:
-          stitchArrays({
-            artists,
-            artistDisplayText,
-            annotation,
-            date,
-            secondDate,
-            dateKind,
-            accessDate,
-            accessKind,
-            body,
-          }),
-      }),
-    },
-  ],
-});
diff --git a/src/data/composite/wiki-data/withRecontextualizedContributionList.js b/src/data/composite/wiki-data/withRecontextualizedContributionList.js
index d2401eac..bcc6e486 100644
--- a/src/data/composite/wiki-data/withRecontextualizedContributionList.js
+++ b/src/data/composite/wiki-data/withRecontextualizedContributionList.js
@@ -10,7 +10,6 @@
 import {input, templateCompositeFrom} from '#composite';
 import {isStringNonEmpty} from '#validators';
 
-import {raiseOutputWithoutDependency} from '#composite/control-flow';
 import {withClonedThings} from '#composite/wiki-data';
 
 export default templateCompositeFrom({
diff --git a/src/data/composite/wiki-data/withResolvedAnnotatedReferenceList.js b/src/data/composite/wiki-data/withResolvedAnnotatedReferenceList.js
index 789a8844..9cc52f29 100644
--- a/src/data/composite/wiki-data/withResolvedAnnotatedReferenceList.js
+++ b/src/data/composite/wiki-data/withResolvedAnnotatedReferenceList.js
@@ -1,15 +1,13 @@
 import {input, templateCompositeFrom} from '#composite';
 import {stitchArrays} from '#sugar';
-import {isDate, isObject, validateArrayItems} from '#validators';
+import {isObject, validateArrayItems} from '#validators';
 
 import {withPropertyFromList} from '#composite/data';
 
-import {
-  exitWithoutDependency,
-  raiseOutputWithoutDependency,
-  withAvailabilityFilter,
-} from '#composite/control-flow';
+import {raiseOutputWithoutDependency, withAvailabilityFilter}
+  from '#composite/control-flow';
 
+import inputSoupyFind from './inputSoupyFind.js';
 import inputNotFoundMode from './inputNotFoundMode.js';
 import inputWikiData from './inputWikiData.js';
 import raiseResolvedReferenceList from './raiseResolvedReferenceList.js';
@@ -24,17 +22,12 @@ export default templateCompositeFrom({
       acceptsNull: true,
     }),
 
-    date: input({
-      validate: isDate,
-      acceptsNull: true,
-    }),
-
     reference: input({type: 'string', defaultValue: 'reference'}),
     annotation: input({type: 'string', defaultValue: 'annotation'}),
     thing: input({type: 'string', defaultValue: 'thing'}),
 
     data: inputWikiData({allowMixedTypes: true}),
-    find: input({type: 'function'}),
+    find: inputSoupyFind(),
 
     notFoundMode: inputNotFoundMode(),
   },
@@ -42,11 +35,6 @@ export default templateCompositeFrom({
   outputs: ['#resolvedAnnotatedReferenceList'],
 
   steps: () => [
-    exitWithoutDependency({
-      dependency: input('data'),
-      value: input.value([]),
-    }),
-
     raiseOutputWithoutDependency({
       dependency: input('list'),
       mode: input.value('empty'),
@@ -98,17 +86,6 @@ export default templateCompositeFrom({
       }),
     },
 
-    {
-      dependencies: ['#matches', input('date')],
-      compute: (continuation, {
-        ['#matches']: matches,
-        [input('date')]: date,
-      }) => continuation({
-        ['#matches']:
-          matches.map(match => ({...match, date})),
-      }),
-    },
-
     withAvailabilityFilter({
       from: '#resolvedReferenceList',
     }),
diff --git a/src/data/composite/wiki-data/withResolvedContribs.js b/src/data/composite/wiki-data/withResolvedContribs.js
index fd3d8a0d..838c991f 100644
--- a/src/data/composite/wiki-data/withResolvedContribs.js
+++ b/src/data/composite/wiki-data/withResolvedContribs.js
@@ -110,6 +110,7 @@ export default templateCompositeFrom({
         '#thingProperty',
         input('artistProperty'),
         input.myself(),
+        'find',
       ],
 
       compute: (continuation, {
@@ -117,6 +118,7 @@ export default templateCompositeFrom({
         ['#thingProperty']: thingProperty,
         [input('artistProperty')]: artistProperty,
         [input.myself()]: myself,
+        ['find']: find,
       }) => continuation({
         ['#contributions']:
           details.map(details => {
@@ -127,6 +129,7 @@ export default templateCompositeFrom({
               thing: myself,
               thingProperty: thingProperty,
               artistProperty: artistProperty,
+              find: find,
             });
 
             return contrib;
diff --git a/src/data/composite/wiki-data/withResolvedReference.js b/src/data/composite/wiki-data/withResolvedReference.js
index ea71707e..6f422194 100644
--- a/src/data/composite/wiki-data/withResolvedReference.js
+++ b/src/data/composite/wiki-data/withResolvedReference.js
@@ -1,16 +1,14 @@
 // Resolves a reference by using the provided find function to match it
-// within the provided thingData dependency. This will early exit if the
-// data dependency is null. Otherwise, the data object is provided on the
-// output dependency, or null, if the reference doesn't match anything or
+// within the provided thingData dependency. The data object is provided on
+// the output dependency, or null, if the reference doesn't match anything or
 // itself was null to begin with.
 
 import {input, templateCompositeFrom} from '#composite';
 
-import {
-  exitWithoutDependency,
-  raiseOutputWithoutDependency,
-} from '#composite/control-flow';
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
 
+import gobbleSoupyFind from './gobbleSoupyFind.js';
+import inputSoupyFind from './inputSoupyFind.js';
 import inputWikiData from './inputWikiData.js';
 
 export default templateCompositeFrom({
@@ -20,7 +18,7 @@ export default templateCompositeFrom({
     ref: input({type: 'string', acceptsNull: true}),
 
     data: inputWikiData({allowMixedTypes: false}),
-    find: input({type: 'function'}),
+    find: inputSoupyFind(),
   },
 
   outputs: ['#resolvedReference'],
@@ -33,24 +31,26 @@ export default templateCompositeFrom({
       }),
     }),
 
-    exitWithoutDependency({
-      dependency: input('data'),
+    gobbleSoupyFind({
+      find: input('find'),
     }),
 
     {
       dependencies: [
         input('ref'),
         input('data'),
-        input('find'),
+        '#find',
       ],
 
       compute: (continuation, {
         [input('ref')]: ref,
         [input('data')]: data,
-        [input('find')]: findFunction,
+        ['#find']: findFunction,
       }) => continuation({
         ['#resolvedReference']:
-          findFunction(ref, data, {mode: 'quiet'}) ?? null,
+          (data
+            ? findFunction(ref, data, {mode: 'quiet'}) ?? null
+            : findFunction(ref, {mode: 'quiet'}) ?? null),
       }),
     },
   ],
diff --git a/src/data/composite/wiki-data/withResolvedReferenceList.js b/src/data/composite/wiki-data/withResolvedReferenceList.js
index 790a962f..9dc960dd 100644
--- a/src/data/composite/wiki-data/withResolvedReferenceList.js
+++ b/src/data/composite/wiki-data/withResolvedReferenceList.js
@@ -1,19 +1,18 @@
 // Resolves a list of references, with each reference matched with provided
-// data in the same way as withResolvedReference. This will early exit if the
-// data dependency is null (even if the reference list is empty). By default
-// it will filter out references which don't match, but this can be changed
-// to early exit ({notFoundMode: 'exit'}) or leave null in place ('null').
+// data in the same way as withResolvedReference. By default it will filter
+// out references which don't match, but this can be changed to early exit
+// ({notFoundMode: 'exit'}) or leave null in place ('null').
 
 import {input, templateCompositeFrom} from '#composite';
 import {isString, validateArrayItems} from '#validators';
 
-import {
-  exitWithoutDependency,
-  raiseOutputWithoutDependency,
-  withAvailabilityFilter,
-} from '#composite/control-flow';
+import {raiseOutputWithoutDependency, withAvailabilityFilter}
+  from '#composite/control-flow';
+import {withMappedList} from '#composite/data';
 
+import gobbleSoupyFind from './gobbleSoupyFind.js';
 import inputNotFoundMode from './inputNotFoundMode.js';
+import inputSoupyFind from './inputSoupyFind.js';
 import inputWikiData from './inputWikiData.js';
 import raiseResolvedReferenceList from './raiseResolvedReferenceList.js';
 
@@ -27,7 +26,7 @@ export default templateCompositeFrom({
     }),
 
     data: inputWikiData({allowMixedTypes: true}),
-    find: input({type: 'function'}),
+    find: inputSoupyFind(),
 
     notFoundMode: inputNotFoundMode(),
   },
@@ -35,11 +34,6 @@ export default templateCompositeFrom({
   outputs: ['#resolvedReferenceList'],
 
   steps: () => [
-    exitWithoutDependency({
-      dependency: input('data'),
-      value: input.value([]),
-    }),
-
     raiseOutputWithoutDependency({
       dependency: input('list'),
       mode: input.value('empty'),
@@ -48,18 +42,30 @@ export default templateCompositeFrom({
       }),
     }),
 
+    gobbleSoupyFind({
+      find: input('find'),
+    }),
+
     {
-      dependencies: [input('list'), input('data'), input('find')],
+      dependencies: [input('data'), '#find'],
       compute: (continuation, {
-        [input('list')]: list,
         [input('data')]: data,
-        [input('find')]: findFunction,
-      }) =>
-        continuation({
-          '#matches': list.map(ref => findFunction(ref, data, {mode: 'quiet'})),
-        }),
+        ['#find']: findFunction,
+      }) => continuation({
+        ['#map']:
+          (data
+            ? ref => findFunction(ref, data, {mode: 'quiet'})
+            : ref => findFunction(ref, {mode: 'quiet'})),
+      }),
     },
 
+    withMappedList({
+      list: input('list'),
+      map: '#map',
+    }).outputs({
+      '#mappedList': '#matches',
+    }),
+
     withAvailabilityFilter({
       from: '#matches',
     }),
diff --git a/src/data/composite/wiki-data/withResolvedSeriesList.js b/src/data/composite/wiki-data/withResolvedSeriesList.js
deleted file mode 100644
index 4ac74cc3..00000000
--- a/src/data/composite/wiki-data/withResolvedSeriesList.js
+++ /dev/null
@@ -1,131 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-import find from '#find';
-import {stitchArrays} from '#sugar';
-import {isSeriesList, validateThing} from '#validators';
-
-import {raiseOutputWithoutDependency} from '#composite/control-flow';
-
-import {
-  fillMissingListItems,
-  withFlattenedList,
-  withUnflattenedList,
-  withPropertiesFromList,
-} from '#composite/data';
-
-import withResolvedReferenceList from './withResolvedReferenceList.js';
-
-export default templateCompositeFrom({
-  annotation: `withResolvedSeriesList`,
-
-  inputs: {
-    group: input({
-      validate: validateThing({referenceType: 'group'}),
-    }),
-
-    list: input({
-      validate: isSeriesList,
-      acceptsNull: true,
-    }),
-  },
-
-  outputs: ['#resolvedSeriesList'],
-
-  steps: () => [
-    raiseOutputWithoutDependency({
-      dependency: input('list'),
-      mode: input.value('empty'),
-      output: input.value({
-        ['#resolvedSeriesList']: [],
-      }),
-    }),
-
-    withPropertiesFromList({
-      list: input('list'),
-      prefix: input.value('#serieses'),
-      properties: input.value([
-        'name',
-        'description',
-        'albums',
-
-        'showAlbumArtists',
-      ]),
-    }),
-
-    fillMissingListItems({
-      list: '#serieses.albums',
-      fill: input.value([]),
-    }),
-
-    withFlattenedList({
-      list: '#serieses.albums',
-    }),
-
-    withResolvedReferenceList({
-      list: '#flattenedList',
-      data: 'albumData',
-      find: input.value(find.album),
-      notFoundMode: input.value('null'),
-    }),
-
-    withUnflattenedList({
-      list: '#resolvedReferenceList',
-    }).outputs({
-      '#unflattenedList': '#serieses.albums',
-    }),
-
-    fillMissingListItems({
-      list: '#serieses.description',
-      fill: input.value(null),
-    }),
-
-    fillMissingListItems({
-      list: '#serieses.showAlbumArtists',
-      fill: input.value(null),
-    }),
-
-    {
-      dependencies: [
-        '#serieses.name',
-        '#serieses.description',
-        '#serieses.albums',
-
-        '#serieses.showAlbumArtists',
-      ],
-
-      compute: (continuation, {
-        ['#serieses.name']: name,
-        ['#serieses.description']: description,
-        ['#serieses.albums']: albums,
-
-        ['#serieses.showAlbumArtists']: showAlbumArtists,
-      }) => continuation({
-        ['#seriesProperties']:
-          stitchArrays({
-            name,
-            description,
-            albums,
-
-            showAlbumArtists,
-          }).map(properties => ({
-              ...properties,
-              group: input
-            }))
-      }),
-    },
-
-    {
-      dependencies: ['#seriesProperties', input('group')],
-      compute: (continuation, {
-        ['#seriesProperties']: seriesProperties,
-        [input('group')]: group,
-      }) => continuation({
-        ['#resolvedSeriesList']:
-          seriesProperties
-            .map(properties => ({
-              ...properties,
-              group,
-            })),
-      }),
-    },
-  ],
-});
diff --git a/src/data/composite/wiki-data/withReverseAnnotatedReferenceList.js b/src/data/composite/wiki-data/withReverseAnnotatedReferenceList.js
deleted file mode 100644
index feae9ccb..00000000
--- a/src/data/composite/wiki-data/withReverseAnnotatedReferenceList.js
+++ /dev/null
@@ -1,116 +0,0 @@
-// Analogous implementation for withReverseReferenceList, for annotated
-// references.
-//
-// Unlike withReverseContributionList, this composition is responsible for
-// "flipping" the directionality of references: in a forward reference list,
-// `thing` points to the thing being referenced, while here, it points to the
-// referencing thing.
-//
-// This behavior can be customized to respect reference lists which are shaped
-// differently than the default and/or to customize the reversed property and
-// provide a less generic label than just "thing".
-
-import withReverseList_template from './helpers/withReverseList-template.js';
-
-import {input} from '#composite';
-import {stitchArrays} from '#sugar';
-
-import {
-  withFlattenedList,
-  withMappedList,
-  withPropertyFromList,
-  withStretchedList,
-} from '#composite/data';
-
-export default withReverseList_template({
-  annotation: `withReverseAnnotatedReferenceList`,
-
-  propertyInputName: 'list',
-  outputName: '#reverseAnnotatedReferenceList',
-
-  additionalInputs: {
-    forward: input({type: 'string', defaultValue: 'thing'}),
-    backward: input({type: 'string', defaultValue: 'thing'}),
-    annotation: input({type: 'string', defaultValue: 'annotation'}),
-  },
-
-  customCompositionSteps: () => [
-    withPropertyFromList({
-      list: input('data'),
-      property: input('list'),
-    }).outputs({
-      '#values': '#referenceLists',
-    }),
-
-    withPropertyFromList({
-      list: '#referenceLists',
-      property: input.value('length'),
-    }),
-
-    withFlattenedList({
-      list: '#referenceLists',
-    }).outputs({
-      '#flattenedList': '#references',
-    }),
-
-    withStretchedList({
-      list: input('data'),
-      lengths: '#referenceLists.length',
-    }).outputs({
-      '#stretchedList': '#things',
-    }),
-
-    withPropertyFromList({
-      list: '#references',
-      property: input('annotation'),
-    }).outputs({
-      '#values': '#annotations',
-    }),
-
-    withPropertyFromList({
-      list: '#references',
-      property: input.value('date'),
-    }).outputs({
-      '#references.date': '#dates',
-    }),
-
-    {
-      dependencies: [
-        input('backward'),
-        input('annotation'),
-        '#things',
-        '#annotations',
-        '#dates',
-      ],
-
-      compute: (continuation, {
-        [input('backward')]: thingProperty,
-        [input('annotation')]: annotationProperty,
-        ['#things']: things,
-        ['#annotations']: annotations,
-        ['#dates']: dates,
-      }) => continuation({
-        '#referencingThings':
-          stitchArrays({
-            [thingProperty]: things,
-            [annotationProperty]: annotations,
-            date: dates,
-          }),
-      }),
-    },
-
-    withPropertyFromList({
-      list: '#references',
-      property: input('forward'),
-    }).outputs({
-      '#values': '#individualReferencedThings',
-    }),
-
-    withMappedList({
-      list: '#individualReferencedThings',
-      map: input.value(thing => [thing]),
-    }).outputs({
-      '#mappedList': '#referencedThings',
-    }),
-  ],
-});
diff --git a/src/data/composite/wiki-data/withReverseContributionList.js b/src/data/composite/wiki-data/withReverseContributionList.js
deleted file mode 100644
index 2396c3b4..00000000
--- a/src/data/composite/wiki-data/withReverseContributionList.js
+++ /dev/null
@@ -1,37 +0,0 @@
-// Analogous implementation for withReverseReferenceList, for contributions.
-
-import withReverseList_template from './helpers/withReverseList-template.js';
-
-import {input} from '#composite';
-
-import {withFlattenedList, withMappedList, withPropertyFromList}
-  from '#composite/data';
-
-export default withReverseList_template({
-  annotation: `withReverseContributionList`,
-
-  propertyInputName: 'list',
-  outputName: '#reverseContributionList',
-
-  customCompositionSteps: () => [
-    withPropertyFromList({
-      list: input('data'),
-      property: input('list'),
-    }).outputs({
-      '#values': '#contributionLists',
-    }),
-
-    withFlattenedList({
-      list: '#contributionLists',
-    }).outputs({
-      '#flattenedList': '#referencingThings',
-    }),
-
-    withMappedList({
-      list: '#referencingThings',
-      map: input.value(contrib => [contrib.artist]),
-    }).outputs({
-      '#mappedList': '#referencedThings',
-    }),
-  ],
-});
diff --git a/src/data/composite/wiki-data/withReverseReferenceList.js b/src/data/composite/wiki-data/withReverseReferenceList.js
index 70d9a58d..906f5bc5 100644
--- a/src/data/composite/wiki-data/withReverseReferenceList.js
+++ b/src/data/composite/wiki-data/withReverseReferenceList.js
@@ -1,44 +1,36 @@
 // Check out the info on reverseReferenceList!
 // This is its composable form.
 
-import withReverseList_template from './helpers/withReverseList-template.js';
+import {input, templateCompositeFrom} from '#composite';
 
-import {input} from '#composite';
+import gobbleSoupyReverse from './gobbleSoupyReverse.js';
+import inputSoupyReverse from './inputSoupyReverse.js';
+import inputWikiData from './inputWikiData.js';
 
-import {withMappedList} from '#composite/data';
+import withResolvedReverse from './helpers/withResolvedReverse.js';
 
-export default withReverseList_template({
+export default templateCompositeFrom({
   annotation: `withReverseReferenceList`,
 
-  propertyInputName: 'list',
-  outputName: '#reverseReferenceList',
-
-  customCompositionSteps: () => [
-    {
-      dependencies: [input('list')],
-      compute: (continuation, {
-        [input('list')]: list,
-      }) => continuation({
-        ['#referenceMap']:
-          thing => thing[list],
-      }),
-    },
-
-    withMappedList({
-      list: input('data'),
-      map: '#referenceMap',
-    }).outputs({
-      '#mappedList': '#referencedThings',
+  inputs: {
+    data: inputWikiData({allowMixedTypes: true}),
+    reverse: inputSoupyReverse(),
+  },
+
+  outputs: ['#reverseReferenceList'],
+
+  steps: () => [
+    gobbleSoupyReverse({
+      reverse: input('reverse'),
     }),
 
-    {
-      dependencies: [input('data')],
-      compute: (continuation, {
-        [input('data')]: data,
-      }) => continuation({
-        ['#referencingThings']:
-          data,
-      }),
-    },
+    // TODO: Check that the reverse spec returns a list.
+
+    withResolvedReverse({
+      data: input('data'),
+      reverse: '#reverse',
+    }).outputs({
+      '#resolvedReverse': '#reverseReferenceList',
+    }),
   ],
 });
diff --git a/src/data/composite/wiki-data/withReverseSingleReferenceList.js b/src/data/composite/wiki-data/withReverseSingleReferenceList.js
deleted file mode 100644
index dd97dc66..00000000
--- a/src/data/composite/wiki-data/withReverseSingleReferenceList.js
+++ /dev/null
@@ -1,50 +0,0 @@
-// Like withReverseReferenceList, but for finding all things which reference
-// the current thing by a property that contains a single reference, rather
-// than within a reference list.
-
-import withReverseList_template from './helpers/withReverseList-template.js';
-
-import {input} from '#composite';
-
-import {withMappedList} from '#composite/data';
-
-export default withReverseList_template({
-  annotation: `withReverseSingleReferenceList`,
-
-  propertyInputName: 'ref',
-  outputName: '#reverseSingleReferenceList',
-
-  customCompositionSteps: () => [
-    {
-      dependencies: [input('data')],
-      compute: (continuation, {
-        [input('data')]: data,
-      }) => continuation({
-        ['#referencingThings']:
-          data,
-      }),
-    },
-
-    // This map wraps each referenced thing in a single-item array.
-    // Each referencing thing references exactly one thing, if any.
-    {
-      dependencies: [input('ref')],
-      compute: (continuation, {
-        [input('ref')]: ref,
-      }) => continuation({
-        ['#singleReferenceMap']:
-          thing =>
-            (thing[ref]
-              ? [thing[ref]]
-              : []),
-      }),
-    },
-
-    withMappedList({
-      list: '#referencingThings',
-      map: '#singleReferenceMap',
-    }).outputs({
-      '#mappedList': '#referencedThings',
-    }),
-  ],
-});
diff --git a/src/data/composite/wiki-data/withUniqueReferencingThing.js b/src/data/composite/wiki-data/withUniqueReferencingThing.js
index 61c10618..7c267038 100644
--- a/src/data/composite/wiki-data/withUniqueReferencingThing.js
+++ b/src/data/composite/wiki-data/withUniqueReferencingThing.js
@@ -4,48 +4,33 @@
 
 import {input, templateCompositeFrom} from '#composite';
 
-import {exitWithoutDependency, raiseOutputWithoutDependency}
-  from '#composite/control-flow';
-
+import gobbleSoupyReverse from './gobbleSoupyReverse.js';
+import inputSoupyReverse from './inputSoupyReverse.js';
 import inputWikiData from './inputWikiData.js';
-import withReverseReferenceList from './withReverseReferenceList.js';
+
+import withResolvedReverse from './helpers/withResolvedReverse.js';
 
 export default templateCompositeFrom({
   annotation: `withUniqueReferencingThing`,
 
   inputs: {
-    data: inputWikiData({allowMixedTypes: false}),
-    list: input({type: 'string'}),
+    data: inputWikiData({allowMixedTypes: true}),
+    reverse: inputSoupyReverse(),
   },
 
   outputs: ['#uniqueReferencingThing'],
 
   steps: () => [
-    // Early exit with null (not an empty array) if the data list
-    // isn't available.
-    exitWithoutDependency({
-      dependency: input('data'),
+    gobbleSoupyReverse({
+      reverse: input('reverse'),
     }),
 
-    withReverseReferenceList({
+    withResolvedReverse({
       data: input('data'),
-      list: input('list'),
+      reverse: '#reverse',
+      options: input.value({unique: true}),
+    }).outputs({
+      '#resolvedReverse': '#uniqueReferencingThing',
     }),
-
-    raiseOutputWithoutDependency({
-      dependency: '#reverseReferenceList',
-      mode: input.value('empty'),
-      output: input.value({'#uniqueReferencingThing': null}),
-    }),
-
-    {
-      dependencies: ['#reverseReferenceList'],
-      compute: (continuation, {
-        ['#reverseReferenceList']: reverseReferenceList,
-      }) => continuation({
-        ['#uniqueReferencingThing']:
-          reverseReferenceList[0],
-      }),
-    },
   ],
 });
diff --git a/src/data/composite/wiki-properties/additionalFiles.js b/src/data/composite/wiki-properties/additionalFiles.js
deleted file mode 100644
index 6760527a..00000000
--- a/src/data/composite/wiki-properties/additionalFiles.js
+++ /dev/null
@@ -1,30 +0,0 @@
-// This is a somewhat more involved data structure - it's for additional
-// or "bonus" files associated with albums or tracks (or anything else).
-// It's got this form:
-//
-//   [
-//     {title: 'Booklet', files: ['Booklet.pdf']},
-//     {
-//       title: 'Wallpaper',
-//       description: 'Cool Wallpaper!',
-//       files: ['1440x900.png', '1920x1080.png']
-//     },
-//     {title: 'Alternate Covers', description: null, files: [...]},
-//     ...
-//   ]
-//
-
-import {isAdditionalFileList} from '#validators';
-
-// TODO: Not templateCompositeFrom.
-
-export default function() {
-  return {
-    flags: {update: true, expose: true},
-    update: {validate: isAdditionalFileList},
-    expose: {
-      transform: (additionalFiles) =>
-        additionalFiles ?? [],
-    },
-  };
-}
diff --git a/src/data/composite/wiki-properties/additionalNameList.js b/src/data/composite/wiki-properties/additionalNameList.js
deleted file mode 100644
index c5971d4a..00000000
--- a/src/data/composite/wiki-properties/additionalNameList.js
+++ /dev/null
@@ -1,14 +0,0 @@
-// A list of additional names! These can be used for a variety of purposes,
-// e.g. providing extra searchable titles, localizations, romanizations or
-// original titles, and so on. Each item has a name and, optionally, a
-// descriptive annotation.
-
-import {isAdditionalNameList} from '#validators';
-
-export default function() {
-  return {
-    flags: {update: true, expose: true},
-    update: {validate: isAdditionalNameList},
-    expose: {transform: value => value ?? []},
-  };
-}
diff --git a/src/data/composite/wiki-properties/annotatedReferenceList.js b/src/data/composite/wiki-properties/annotatedReferenceList.js
index d6364475..8e6c96a1 100644
--- a/src/data/composite/wiki-properties/annotatedReferenceList.js
+++ b/src/data/composite/wiki-properties/annotatedReferenceList.js
@@ -1,10 +1,7 @@
 import {input, templateCompositeFrom} from '#composite';
-import find from '#find';
-import {combineWikiDataArrays} from '#wiki-data';
 
 import {
   isContentString,
-  isDate,
   optional,
   validateArrayItems,
   validateProperties,
@@ -12,7 +9,7 @@ import {
 } from '#validators';
 
 import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withResolvedAnnotatedReferenceList}
+import {inputSoupyFind, inputWikiData, withResolvedAnnotatedReferenceList}
   from '#composite/wiki-data';
 
 import {referenceListInputDescriptions, referenceListUpdateDescription}
@@ -27,12 +24,7 @@ export default templateCompositeFrom({
     ...referenceListInputDescriptions(),
 
     data: inputWikiData({allowMixedTypes: true}),
-    find: input({type: 'function'}),
-
-    date: input({
-      validate: isDate,
-      acceptsNull: true,
-    }),
+    find: inputSoupyFind(),
 
     reference: input.staticValue({type: 'string', defaultValue: 'reference'}),
     annotation: input.staticValue({type: 'string', defaultValue: 'annotation'}),
@@ -59,8 +51,6 @@ export default templateCompositeFrom({
     withResolvedAnnotatedReferenceList({
       list: input.updateValue(),
 
-      date: input('date'),
-
       reference: input('reference'),
       annotation: input('annotation'),
       thing: input('thing'),
diff --git a/src/data/composite/wiki-properties/commentary.js b/src/data/composite/wiki-properties/commentary.js
deleted file mode 100644
index cd6b7ac4..00000000
--- a/src/data/composite/wiki-properties/commentary.js
+++ /dev/null
@@ -1,30 +0,0 @@
-// Artist commentary! Generally present on tracks and albums.
-
-import {input, templateCompositeFrom} from '#composite';
-import {isCommentary} from '#validators';
-
-import {exitWithoutDependency, exposeDependency}
-  from '#composite/control-flow';
-import {withParsedCommentaryEntries} from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `commentary`,
-
-  compose: false,
-
-  steps: () => [
-    exitWithoutDependency({
-      dependency: input.updateValue({validate: isCommentary}),
-      mode: input.value('falsy'),
-      value: input.value(null),
-    }),
-
-    withParsedCommentaryEntries({
-      from: input.updateValue(),
-    }),
-
-    exposeDependency({
-      dependency: '#parsedCommentaryEntries',
-    }),
-  ],
-});
diff --git a/src/data/composite/wiki-properties/commentatorArtists.js b/src/data/composite/wiki-properties/commentatorArtists.js
index c5c14769..54d3e1a5 100644
--- a/src/data/composite/wiki-properties/commentatorArtists.js
+++ b/src/data/composite/wiki-properties/commentatorArtists.js
@@ -7,7 +7,6 @@ import {exitWithoutDependency, exposeDependency}
   from '#composite/control-flow';
 import {withFlattenedList, withPropertyFromList, withUniqueItemsOnly}
   from '#composite/data';
-import {withParsedCommentaryEntries} from '#composite/wiki-data';
 
 export default templateCompositeFrom({
   annotation: `commentatorArtists`,
@@ -21,19 +20,13 @@ export default templateCompositeFrom({
       value: input.value([]),
     }),
 
-    withParsedCommentaryEntries({
-      from: 'commentary',
-    }),
-
     withPropertyFromList({
-      list: '#parsedCommentaryEntries',
+      list: 'commentary',
       property: input.value('artists'),
-    }).outputs({
-      '#parsedCommentaryEntries.artists': '#artistLists',
     }),
 
     withFlattenedList({
-      list: '#artistLists',
+      list: '#commentary.artists',
     }).outputs({
       '#flattenedList': '#artists',
     }),
diff --git a/src/data/composite/wiki-properties/constitutibleArtwork.js b/src/data/composite/wiki-properties/constitutibleArtwork.js
new file mode 100644
index 00000000..48f4211a
--- /dev/null
+++ b/src/data/composite/wiki-properties/constitutibleArtwork.js
@@ -0,0 +1,70 @@
+// This composition does not actually inspect the values of any properties
+// specified, so it's not responsible for determining whether a constituted
+// artwork should exist at all.
+
+import {input, templateCompositeFrom} from '#composite';
+import {withEntries} from '#sugar';
+import Thing from '#thing';
+import {validateThing} from '#validators';
+
+import {exposeDependency, exposeUpdateValueOrContinue}
+  from '#composite/control-flow';
+import {withConstitutedArtwork} from '#composite/wiki-data';
+
+const template = templateCompositeFrom({
+  annotation: `constitutibleArtwork`,
+
+  compose: false,
+
+  inputs: {
+    thingProperty: input({type: 'string', acceptsNull: true}),
+    dimensionsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    fileExtensionFromThingProperty: input({type: 'string', acceptsNull: true}),
+    dateFromThingProperty: input({type: 'string', acceptsNull: true}),
+    artistContribsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    artistContribsArtistProperty: input({type: 'string', acceptsNull: true}),
+    artTagsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    referencedArtworksFromThingProperty: input({type: 'string', acceptsNull: true}),
+  },
+
+  steps: () => [
+    exposeUpdateValueOrContinue({
+      validate: input.value(
+        validateThing({
+          referenceType: 'artwork',
+        })),
+    }),
+
+    withConstitutedArtwork({
+      thingProperty: input('thingProperty'),
+      dimensionsFromThingProperty: input('dimensionsFromThingProperty'),
+      fileExtensionFromThingProperty: input('fileExtensionFromThingProperty'),
+      dateFromThingProperty: input('dateFromThingProperty'),
+      artistContribsFromThingProperty: input('artistContribsFromThingProperty'),
+      artistContribsArtistProperty: input('artistContribsArtistProperty'),
+      artTagsFromThingProperty: input('artTagsFromThingProperty'),
+      referencedArtworksFromThingProperty: input('referencedArtworksFromThingProperty'),
+    }),
+
+    exposeDependency({
+      dependency: '#constitutedArtwork',
+    }),
+  ],
+});
+
+template.fromYAMLFieldSpec = function(field) {
+  const {[Thing.yamlDocumentSpec]: documentSpec} = this;
+
+  const {provide} = documentSpec.fields[field].transform;
+
+  const inputs =
+    withEntries(provide, entries =>
+      entries.map(([property, value]) => [
+        property,
+        input.value(value),
+      ]));
+
+  return template(inputs);
+};
+
+export default template;
diff --git a/src/data/composite/wiki-properties/constitutibleArtworkList.js b/src/data/composite/wiki-properties/constitutibleArtworkList.js
new file mode 100644
index 00000000..dad3a957
--- /dev/null
+++ b/src/data/composite/wiki-properties/constitutibleArtworkList.js
@@ -0,0 +1,72 @@
+// This composition does not actually inspect the values of any properties
+// specified, so it's not responsible for determining whether a constituted
+// artwork should exist at all.
+
+import {input, templateCompositeFrom} from '#composite';
+import {withEntries} from '#sugar';
+import Thing from '#thing';
+import {validateWikiData} from '#validators';
+
+import {exposeUpdateValueOrContinue} from '#composite/control-flow';
+import {withConstitutedArtwork} from '#composite/wiki-data';
+
+const template = templateCompositeFrom({
+  annotation: `constitutibleArtworkList`,
+
+  compose: false,
+
+  inputs: {
+    thingProperty: input({type: 'string', acceptsNull: true}),
+    dimensionsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    fileExtensionFromThingProperty: input({type: 'string', acceptsNull: true}),
+    dateFromThingProperty: input({type: 'string', acceptsNull: true}),
+    artistContribsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    artistContribsArtistProperty: input({type: 'string', acceptsNull: true}),
+    artTagsFromThingProperty: input({type: 'string', acceptsNull: true}),
+    referencedArtworksFromThingProperty: input({type: 'string', acceptsNull: true}),
+  },
+
+  steps: () => [
+    exposeUpdateValueOrContinue({
+      validate: input.value(
+        validateWikiData({
+          referenceType: 'artwork',
+        })),
+    }),
+
+    withConstitutedArtwork({
+      thingProperty: input('thingProperty'),
+      dimensionsFromThingProperty: input('dimensionsFromThingProperty'),
+      fileExtensionFromThingProperty: input('fileExtensionFromThingProperty'),
+      dateFromThingProperty: input('dateFromThingProperty'),
+      artistContribsFromThingProperty: input('artistContribsFromThingProperty'),
+      artistContribsArtistProperty: input('artistContribsArtistProperty'),
+      artTagsFromThingProperty: input('artTagsFromThingProperty'),
+      referencedArtworksFromThingProperty: input('referencedArtworksFromThingProperty'),
+    }),
+
+    {
+      dependencies: ['#constitutedArtwork'],
+      compute: ({
+        ['#constitutedArtwork']: constitutedArtwork,
+      }) => [constitutedArtwork],
+    },
+  ],
+});
+
+template.fromYAMLFieldSpec = function(field) {
+  const {[Thing.yamlDocumentSpec]: documentSpec} = this;
+
+  const {provide} = documentSpec.fields[field].transform;
+
+  const inputs =
+    withEntries(provide, entries =>
+      entries.map(([property, value]) => [
+        property,
+        input.value(value),
+      ]));
+
+  return template(inputs);
+};
+
+export default template;
diff --git a/src/data/composite/wiki-properties/directory.js b/src/data/composite/wiki-properties/directory.js
index 9ca2a204..1756a8e5 100644
--- a/src/data/composite/wiki-properties/directory.js
+++ b/src/data/composite/wiki-properties/directory.js
@@ -18,6 +18,7 @@ export default templateCompositeFrom({
     name: input({
       validate: isName,
       defaultDependency: 'name',
+      acceptsNull: true,
     }),
 
     suffix: input({
diff --git a/src/data/composite/wiki-properties/index.js b/src/data/composite/wiki-properties/index.js
index b55616c0..e8f109d3 100644
--- a/src/data/composite/wiki-properties/index.js
+++ b/src/data/composite/wiki-properties/index.js
@@ -3,12 +3,11 @@
 // Entries here may depend on entries in #composite/control-flow,
 // #composite/data, and #composite/wiki-data.
 
-export {default as additionalFiles} from './additionalFiles.js';
-export {default as additionalNameList} from './additionalNameList.js';
 export {default as annotatedReferenceList} from './annotatedReferenceList.js';
 export {default as color} from './color.js';
-export {default as commentary} from './commentary.js';
 export {default as commentatorArtists} from './commentatorArtists.js';
+export {default as constitutibleArtwork} from './constitutibleArtwork.js';
+export {default as constitutibleArtworkList} from './constitutibleArtworkList.js';
 export {default as contentString} from './contentString.js';
 export {default as contribsPresent} from './contribsPresent.js';
 export {default as contributionList} from './contributionList.js';
@@ -21,15 +20,12 @@ export {default as flag} from './flag.js';
 export {default as name} from './name.js';
 export {default as referenceList} from './referenceList.js';
 export {default as referencedArtworkList} from './referencedArtworkList.js';
-export {default as reverseAnnotatedReferenceList} from './reverseAnnotatedReferenceList.js';
-export {default as reverseContributionList} from './reverseContributionList.js';
 export {default as reverseReferenceList} from './reverseReferenceList.js';
-export {default as reverseReferencedArtworkList} from './reverseReferencedArtworkList.js';
-export {default as reverseSingleReferenceList} from './reverseSingleReferenceList.js';
-export {default as seriesList} from './seriesList.js';
 export {default as simpleDate} from './simpleDate.js';
 export {default as simpleString} from './simpleString.js';
 export {default as singleReference} from './singleReference.js';
+export {default as soupyFind} from './soupyFind.js';
+export {default as soupyReverse} from './soupyReverse.js';
 export {default as thing} from './thing.js';
 export {default as thingList} from './thingList.js';
 export {default as urls} from './urls.js';
diff --git a/src/data/composite/wiki-properties/referenceList.js b/src/data/composite/wiki-properties/referenceList.js
index 4d4cb106..4f8207b5 100644
--- a/src/data/composite/wiki-properties/referenceList.js
+++ b/src/data/composite/wiki-properties/referenceList.js
@@ -11,7 +11,8 @@ import {input, templateCompositeFrom} from '#composite';
 import {validateReferenceList} from '#validators';
 
 import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withResolvedReferenceList} from '#composite/wiki-data';
+import {inputSoupyFind, inputWikiData, withResolvedReferenceList}
+  from '#composite/wiki-data';
 
 import {referenceListInputDescriptions, referenceListUpdateDescription}
   from './helpers/reference-list-helpers.js';
@@ -25,7 +26,7 @@ export default templateCompositeFrom({
     ...referenceListInputDescriptions(),
 
     data: inputWikiData({allowMixedTypes: true}),
-    find: input({type: 'function'}),
+    find: inputSoupyFind(),
   },
 
   update:
diff --git a/src/data/composite/wiki-properties/referencedArtworkList.js b/src/data/composite/wiki-properties/referencedArtworkList.js
index 819b2f43..4f243493 100644
--- a/src/data/composite/wiki-properties/referencedArtworkList.js
+++ b/src/data/composite/wiki-properties/referencedArtworkList.js
@@ -1,7 +1,5 @@
 import {input, templateCompositeFrom} from '#composite';
 import find from '#find';
-import {isDate} from '#validators';
-import {combineWikiDataArrays} from '#wiki-data';
 
 import annotatedReferenceList from './annotatedReferenceList.js';
 
@@ -10,47 +8,24 @@ export default templateCompositeFrom({
 
   compose: false,
 
-  inputs: {
-    date: input({
-      validate: isDate,
-      acceptsNull: true,
-    }),
-  },
-
   steps: () => [
     {
-      dependencies: [
-        'albumData',
-        'trackData',
-      ],
-
-      compute: (continuation, {
-        albumData,
-        trackData,
-      }) => continuation({
-        ['#data']:
-          combineWikiDataArrays([
-            albumData,
-            trackData,
-          ]),
-      }),
-    },
-
-    {
       compute: (continuation) => continuation({
         ['#find']:
           find.mixed({
-            track: find.trackWithArtwork,
-            album: find.albumWithArtwork,
+            track: find.trackPrimaryArtwork,
+            album: find.albumPrimaryArtwork,
           }),
       }),
     },
 
     annotatedReferenceList({
       referenceType: input.value(['album', 'track']),
-      data: '#data',
+
+      data: 'artworkData',
       find: '#find',
-      date: input('date'),
+
+      thing: input.value('artwork'),
     }),
   ],
 });
diff --git a/src/data/composite/wiki-properties/reverseAnnotatedReferenceList.js b/src/data/composite/wiki-properties/reverseAnnotatedReferenceList.js
deleted file mode 100644
index ba7166b9..00000000
--- a/src/data/composite/wiki-properties/reverseAnnotatedReferenceList.js
+++ /dev/null
@@ -1,33 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-
-import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withReverseAnnotatedReferenceList}
-  from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `reverseAnnotatedReferenceList`,
-
-  compose: false,
-
-  inputs: {
-    data: inputWikiData({allowMixedTypes: false}),
-    list: input({type: 'string'}),
-
-    forward: input({type: 'string', defaultValue: 'thing'}),
-    backward: input({type: 'string', defaultValue: 'thing'}),
-    annotation: input({type: 'string', defaultValue: 'annotation'}),
-  },
-
-  steps: () => [
-    withReverseAnnotatedReferenceList({
-      data: input('data'),
-      list: input('list'),
-
-      forward: input('forward'),
-      backward: input('backward'),
-      annotation: input('annotation'),
-    }),
-
-    exposeDependency({dependency: '#reverseAnnotatedReferenceList'}),
-  ],
-});
diff --git a/src/data/composite/wiki-properties/reverseContributionList.js b/src/data/composite/wiki-properties/reverseContributionList.js
deleted file mode 100644
index 7f3f9c81..00000000
--- a/src/data/composite/wiki-properties/reverseContributionList.js
+++ /dev/null
@@ -1,24 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-
-import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withReverseContributionList} from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `reverseContributionList`,
-
-  compose: false,
-
-  inputs: {
-    data: inputWikiData({allowMixedTypes: false}),
-    list: input({type: 'string'}),
-  },
-
-  steps: () => [
-    withReverseContributionList({
-      data: input('data'),
-      list: input('list'),
-    }),
-
-    exposeDependency({dependency: '#reverseContributionList'}),
-  ],
-});
diff --git a/src/data/composite/wiki-properties/reverseReferenceList.js b/src/data/composite/wiki-properties/reverseReferenceList.js
index 84ba67df..6d590a67 100644
--- a/src/data/composite/wiki-properties/reverseReferenceList.js
+++ b/src/data/composite/wiki-properties/reverseReferenceList.js
@@ -1,13 +1,13 @@
 // Neat little shortcut for "reversing" the reference lists stored on other
 // things - for example, tracks specify a "referenced tracks" property, and
 // you would use this to compute a corresponding "referenced *by* tracks"
-// property. Naturally, the passed ref list property is of the things in the
-// wiki data provided, not the requesting Thing itself.
+// property.
 
 import {input, templateCompositeFrom} from '#composite';
 
 import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withReverseReferenceList} from '#composite/wiki-data';
+import {inputSoupyReverse, inputWikiData, withReverseReferenceList}
+  from '#composite/wiki-data';
 
 export default templateCompositeFrom({
   annotation: `reverseReferenceList`,
@@ -15,14 +15,14 @@ export default templateCompositeFrom({
   compose: false,
 
   inputs: {
-    data: inputWikiData({allowMixedTypes: false}),
-    list: input({type: 'string'}),
+    data: inputWikiData({allowMixedTypes: true}),
+    reverse: inputSoupyReverse(),
   },
 
   steps: () => [
     withReverseReferenceList({
       data: input('data'),
-      list: input('list'),
+      reverse: input('reverse'),
     }),
 
     exposeDependency({dependency: '#reverseReferenceList'}),
diff --git a/src/data/composite/wiki-properties/reverseReferencedArtworkList.js b/src/data/composite/wiki-properties/reverseReferencedArtworkList.js
deleted file mode 100644
index 2950bdb9..00000000
--- a/src/data/composite/wiki-properties/reverseReferencedArtworkList.js
+++ /dev/null
@@ -1,39 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-import {combineWikiDataArrays} from '#wiki-data';
-
-import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withReverseAnnotatedReferenceList}
-  from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `reverseReferencedArtworkList`,
-
-  compose: false,
-
-  steps: () => [
-    {
-      dependencies: [
-        'albumData',
-        'trackData',
-      ],
-
-      compute: (continuation, {
-        albumData,
-        trackData,
-      }) => continuation({
-        ['#data']:
-          combineWikiDataArrays([
-            albumData,
-            trackData,
-          ]),
-      }),
-    },
-
-    withReverseAnnotatedReferenceList({
-      data: '#data',
-      list: input.value('referencedArtworks'),
-    }),
-
-    exposeDependency({dependency: '#reverseAnnotatedReferenceList'}),
-  ],
-});
diff --git a/src/data/composite/wiki-properties/reverseSingleReferenceList.js b/src/data/composite/wiki-properties/reverseSingleReferenceList.js
deleted file mode 100644
index d180b12d..00000000
--- a/src/data/composite/wiki-properties/reverseSingleReferenceList.js
+++ /dev/null
@@ -1,24 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-
-import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withReverseSingleReferenceList} from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `reverseSingleReferenceList`,
-
-  compose: false,
-
-  inputs: {
-    data: inputWikiData({allowMixedTypes: false}),
-    ref: input({type: 'string'}),
-  },
-
-  steps: () => [
-    withReverseSingleReferenceList({
-      data: input('data'),
-      ref: input('ref'),
-    }),
-
-    exposeDependency({dependency: '#reverseSingleReferenceList'}),
-  ],
-});
diff --git a/src/data/composite/wiki-properties/seriesList.js b/src/data/composite/wiki-properties/seriesList.js
deleted file mode 100644
index 2a101b45..00000000
--- a/src/data/composite/wiki-properties/seriesList.js
+++ /dev/null
@@ -1,31 +0,0 @@
-import {input, templateCompositeFrom} from '#composite';
-import {isSeriesList, validateThing} from '#validators';
-
-import {exposeDependency} from '#composite/control-flow';
-import {withResolvedSeriesList} from '#composite/wiki-data';
-
-export default templateCompositeFrom({
-  annotation: `seriesList`,
-
-  compose: false,
-
-  inputs: {
-    group: input({
-      validate: validateThing({referenceType: 'group'}),
-    }),
-  },
-
-  steps: () => [
-    withResolvedSeriesList({
-      group: input('group'),
-
-      list: input.updateValue({
-        validate: isSeriesList,
-      }),
-    }),
-
-    exposeDependency({
-      dependency: '#resolvedSeriesList',
-    }),
-  ],
-});
diff --git a/src/data/composite/wiki-properties/singleReference.js b/src/data/composite/wiki-properties/singleReference.js
index db4fc9f9..f532ebbe 100644
--- a/src/data/composite/wiki-properties/singleReference.js
+++ b/src/data/composite/wiki-properties/singleReference.js
@@ -11,7 +11,8 @@ import {input, templateCompositeFrom} from '#composite';
 import {isThingClass, validateReference} from '#validators';
 
 import {exposeDependency} from '#composite/control-flow';
-import {inputWikiData, withResolvedReference} from '#composite/wiki-data';
+import {inputSoupyFind, inputWikiData, withResolvedReference}
+  from '#composite/wiki-data';
 
 export default templateCompositeFrom({
   annotation: `singleReference`,
@@ -21,8 +22,7 @@ export default templateCompositeFrom({
   inputs: {
     class: input.staticValue({validate: isThingClass}),
 
-    find: input({type: 'function'}),
-
+    find: inputSoupyFind(),
     data: inputWikiData({allowMixedTypes: false}),
   },
 
diff --git a/src/data/composite/wiki-properties/soupyFind.js b/src/data/composite/wiki-properties/soupyFind.js
new file mode 100644
index 00000000..0f9a17e3
--- /dev/null
+++ b/src/data/composite/wiki-properties/soupyFind.js
@@ -0,0 +1,14 @@
+import {isObject} from '#validators';
+
+import {inputSoupyFind} from '#composite/wiki-data';
+
+function soupyFind() {
+  return {
+    flags: {update: true},
+    update: {validate: isObject},
+  };
+}
+
+soupyFind.input = inputSoupyFind.input;
+
+export default soupyFind;
diff --git a/src/data/composite/wiki-properties/soupyReverse.js b/src/data/composite/wiki-properties/soupyReverse.js
new file mode 100644
index 00000000..784a66b4
--- /dev/null
+++ b/src/data/composite/wiki-properties/soupyReverse.js
@@ -0,0 +1,37 @@
+import {isObject} from '#validators';
+
+import {inputSoupyReverse} from '#composite/wiki-data';
+
+function soupyReverse() {
+  return {
+    flags: {update: true},
+    update: {validate: isObject},
+  };
+}
+
+soupyReverse.input = inputSoupyReverse.input;
+
+soupyReverse.contributionsBy =
+  (bindTo, contributionsProperty) => ({
+    bindTo,
+
+    referencing: thing => thing[contributionsProperty],
+    referenced: contrib => [contrib.artist],
+  });
+
+soupyReverse.artworkContributionsBy =
+  (bindTo, artworkProperty, {single = false} = {}) => ({
+    bindTo,
+
+    referencing: thing =>
+      (single
+        ? (thing[artworkProperty]
+            ? thing[artworkProperty].artistContribs
+            : [])
+        : thing[artworkProperty]
+            .flatMap(artwork => artwork.artistContribs)),
+
+    referenced: contrib => [contrib.artist],
+  });
+
+export default soupyReverse;
diff --git a/src/data/thing.js b/src/data/thing.js
index 78ad3642..f719224d 100644
--- a/src/data/thing.js
+++ b/src/data/thing.js
@@ -16,9 +16,19 @@ export default class Thing extends CacheableObject {
   static findSpecs = Symbol.for('Thing.findSpecs');
   static findThisThingOnly = Symbol.for('Thing.findThisThingOnly');
 
+  static reverseSpecs = Symbol.for('Thing.reverseSpecs');
+
   static yamlDocumentSpec = Symbol.for('Thing.yamlDocumentSpec');
   static getYamlLoadingSpec = Symbol.for('Thing.getYamlLoadingSpec');
 
+  static yamlSourceFilename = Symbol.for('Thing.yamlSourceFilename');
+  static yamlSourceDocument = Symbol.for('Thing.yamlSourceDocument');
+  static yamlSourceDocumentPlacement = Symbol.for('Thing.yamlSourceDocumentPlacement');
+
+  [Symbol.for('Thing.yamlSourceFilename')] = null;
+  [Symbol.for('Thing.yamlSourceDocument')] = null;
+  [Symbol.for('Thing.yamlSourceDocumentPlacement')] = null;
+
   static isThingConstructor = Symbol.for('Thing.isThingConstructor');
   static isThing = Symbol.for('Thing.isThing');
 
@@ -26,14 +36,15 @@ export default class Thing extends CacheableObject {
   // Symbol.for('Thing.isThingConstructor') in constructor
   static [Symbol.for('Thing.isThingConstructor')] = NaN;
 
-  static [CacheableObject.propertyDescriptors] = {
+  constructor() {
+    super({seal: false});
+
     // To detect:
     // Object.hasOwn(object, Symbol.for('Thing.isThing'))
-    [Symbol.for('Thing.isThing')]: {
-      flags: {expose: true},
-      expose: {compute: () => NaN},
-    },
-  };
+    this[Symbol.for('Thing.isThing')] = NaN;
+
+    Object.seal(this);
+  }
 
   static [Symbol.for('Thing.selectAll')] = _wikiData => [];
 
@@ -49,7 +60,7 @@ export default class Thing extends CacheableObject {
       if (this.name) {
         name = colors.green(`"${this.name}"`);
       }
-    } catch (error) {
+    } catch {
       name = colors.yellow(`couldn't get name`);
     }
 
@@ -58,7 +69,7 @@ export default class Thing extends CacheableObject {
       if (this.directory) {
         reference = colors.blue(Thing.getReference(this));
       }
-    } catch (error) {
+    } catch {
       reference = colors.yellow(`couldn't get reference`);
     }
 
diff --git a/src/data/things/additional-file.js b/src/data/things/additional-file.js
new file mode 100644
index 00000000..398d0af5
--- /dev/null
+++ b/src/data/things/additional-file.js
@@ -0,0 +1,47 @@
+import {input} from '#composite';
+import Thing from '#thing';
+import {isString, validateArrayItems} from '#validators';
+
+import {contentString, simpleString, thing} from '#composite/wiki-properties';
+
+import {exposeConstant, exposeUpdateValueOrContinue}
+  from '#composite/control-flow';
+
+export class AdditionalFile extends Thing {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    thing: thing(),
+
+    title: simpleString(),
+
+    description: contentString(),
+
+    filenames: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(validateArrayItems(isString)),
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Title': {property: 'title'},
+      'Description': {property: 'description'},
+      'Files': {property: 'filenames'},
+    },
+  };
+
+  get paths() {
+    if (!this.thing) return null;
+    if (!this.thing.getOwnAdditionalFilePath) return null;
+
+    return (
+      this.filenames.map(filename =>
+        this.thing.getOwnAdditionalFilePath(this, filename)));
+  }
+}
diff --git a/src/data/things/additional-name.js b/src/data/things/additional-name.js
new file mode 100644
index 00000000..4c23f291
--- /dev/null
+++ b/src/data/things/additional-name.js
@@ -0,0 +1,21 @@
+import Thing from '#thing';
+
+import {contentString, thing} from '#composite/wiki-properties';
+
+export class AdditionalName extends Thing {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    thing: thing(),
+
+    name: contentString(),
+    annotation: contentString(),
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Name': {property: 'name'},
+      'Annotation': {property: 'annotation'},
+    },
+  };
+}
diff --git a/src/data/things/album.js b/src/data/things/album.js
index bd54a356..5132b962 100644
--- a/src/data/things/album.js
+++ b/src/data/things/album.js
@@ -6,18 +6,20 @@ import {inspect} from 'node:util';
 import CacheableObject from '#cacheable-object';
 import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import {traverse} from '#node-utils';
 import {sortAlbumsTracksChronologically, sortChronologically} from '#sort';
-import {accumulateSum, empty} from '#sugar';
+import {empty} from '#sugar';
 import Thing from '#thing';
-import {isColor, isDate, isDirectory, validateWikiData} from '#validators';
+import {isColor, isDate, isDirectory, isNumber} from '#validators';
 
 import {
   parseAdditionalFiles,
   parseAdditionalNames,
   parseAnnotatedReferences,
+  parseArtwork,
+  parseCommentary,
   parseContributors,
+  parseCreditingSources,
   parseDate,
   parseDimensions,
   parseWallpaperParts,
@@ -27,19 +29,14 @@ import {exitWithoutDependency, exposeDependency, exposeUpdateValueOrContinue}
   from '#composite/control-flow';
 import {withPropertyFromObject} from '#composite/data';
 
-import {
-  exitWithoutContribs,
-  withDirectory,
-  withResolvedReference,
-  withCoverArtDate,
-} from '#composite/wiki-data';
+import {exitWithoutContribs, withDirectory, withCoverArtDate}
+  from '#composite/wiki-data';
 
 import {
-  additionalFiles,
-  additionalNameList,
-  commentary,
   color,
   commentatorArtists,
+  constitutibleArtwork,
+  constitutibleArtworkList,
   contentString,
   contribsPresent,
   contributionList,
@@ -50,10 +47,10 @@ import {
   name,
   referencedArtworkList,
   referenceList,
-  reverseReferencedArtworkList,
   simpleDate,
   simpleString,
-  singleReference,
+  soupyFind,
+  soupyReverse,
   thing,
   thingList,
   urls,
@@ -61,17 +58,21 @@ import {
   wikiData,
 } from '#composite/wiki-properties';
 
-import {withTracks} from '#composite/things/album';
-import {withAlbum} from '#composite/things/track-section';
+import {withHasCoverArt, withTracks} from '#composite/things/album';
+import {withAlbum, withContinueCountingFrom, withStartCountingFrom}
+  from '#composite/things/track-section';
 
 export class Album extends Thing {
   static [Thing.referenceType] = 'album';
 
   static [Thing.getPropertyDescriptors] = ({
+    AdditionalFile,
+    AdditionalName,
     ArtTag,
-    Artist,
+    Artwork,
+    CommentaryEntry,
+    CreditingSourcesEntry,
     Group,
-    Track,
     TrackSection,
     WikiInfo,
   }) => ({
@@ -92,13 +93,18 @@ export class Album extends Thing {
       }),
     ],
 
+    alwaysReferenceByDirectory: flag(false),
     alwaysReferenceTracksByDirectory: flag(false),
     suffixTrackDirectories: flag(false),
 
+    countTracksInArtistTotals: flag(true),
+
     color: color(),
     urls: urls(),
 
-    additionalNames: additionalNameList(),
+    additionalNames: thingList({
+      class: input.value(AdditionalName),
+    }),
 
     bandcampAlbumIdentifier: simpleString(),
     bandcampArtworkIdentifier: simpleString(),
@@ -108,16 +114,10 @@ export class Album extends Thing {
     dateAddedToWiki: simpleDate(),
 
     coverArtDate: [
-      // ~~TODO: Why does this fall back, but Track.coverArtDate doesn't?~~
-      // TODO: OK so it's because tracks don't *store* dates just like that.
-      // Really instead of fallback being a flag, it should be a date value,
-      // if this option is worth existing at all.
       withCoverArtDate({
         from: input.updateValue({
           validate: isDate,
         }),
-
-        fallback: input.value(true),
       }),
 
       exposeDependency({dependency: '#coverArtDate'}),
@@ -146,7 +146,11 @@ export class Album extends Thing {
     ],
 
     wallpaperParts: [
-      exitWithoutContribs({contribs: 'wallpaperArtistContribs'}),
+      exitWithoutContribs({
+        contribs: 'wallpaperArtistContribs',
+        value: input.value([]),
+      }),
+
       wallpaperParts(),
     ],
 
@@ -167,13 +171,56 @@ export class Album extends Thing {
       dimensions(),
     ],
 
+    wallpaperArtwork: [
+      exitWithoutDependency({
+        dependency: 'wallpaperArtistContribs',
+        mode: input.value('empty'),
+        value: input.value(null),
+      }),
+
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Wallpaper Artwork'),
+    ],
+
+    bannerArtwork: [
+      exitWithoutDependency({
+        dependency: 'bannerArtistContribs',
+        mode: input.value('empty'),
+        value: input.value(null),
+      }),
+
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Banner Artwork'),
+    ],
+
+    coverArtworks: [
+      withHasCoverArt(),
+
+      exitWithoutDependency({
+        dependency: '#hasCoverArt',
+        mode: input.value('falsy'),
+        value: input.value([]),
+      }),
+
+      constitutibleArtworkList.fromYAMLFieldSpec
+        .call(this, 'Cover Artwork'),
+    ],
+
     hasTrackNumbers: flag(true),
     isListedOnHomepage: flag(true),
     isListedInGalleries: flag(true),
 
-    commentary: commentary(),
-    creditSources: commentary(),
-    additionalFiles: additionalFiles(),
+    commentary: thingList({
+      class: input.value(CommentaryEntry),
+    }),
+
+    creditingSources: thingList({
+      class: input.value(CreditingSourcesEntry),
+    }),
+
+    additionalFiles: thingList({
+      class: input.value(AdditionalFile),
+    }),
 
     trackSections: thingList({
       class: input.value(TrackSection),
@@ -185,9 +232,7 @@ export class Album extends Thing {
     }),
 
     coverArtistContribs: [
-      withCoverArtDate({
-        fallback: input.value(true),
-      }),
+      withCoverArtDate(),
 
       contributionList({
         date: '#coverArtDate',
@@ -206,9 +251,7 @@ export class Album extends Thing {
     }),
 
     wallpaperArtistContribs: [
-      withCoverArtDate({
-        fallback: input.value(true),
-      }),
+      withCoverArtDate(),
 
       contributionList({
         date: '#coverArtDate',
@@ -217,9 +260,7 @@ export class Album extends Thing {
     ],
 
     bannerArtistContribs: [
-      withCoverArtDate({
-        fallback: input.value(true),
-      }),
+      withCoverArtDate(),
 
       contributionList({
         date: '#coverArtDate',
@@ -229,8 +270,7 @@ export class Album extends Thing {
 
     groups: referenceList({
       class: input.value(Group),
-      find: input.value(find.group),
-      data: 'groupData',
+      find: soupyFind.input('group'),
     }),
 
     artTags: [
@@ -241,8 +281,7 @@ export class Album extends Thing {
 
       referenceList({
         class: input.value(ArtTag),
-        find: input.value(find.artTag),
-        data: 'artTagData',
+        find: soupyFind.input('artTag'),
       }),
     ],
 
@@ -252,44 +291,20 @@ export class Album extends Thing {
         value: input.value([]),
       }),
 
-      {
-        dependencies: ['coverArtDate', 'date'],
-        compute: (continuation, {
-          coverArtDate,
-          date,
-        }) => continuation({
-          ['#date']:
-            coverArtDate ?? date,
-        }),
-      },
-
-      referencedArtworkList({
-        date: '#date',
-      }),
+      referencedArtworkList(),
     ],
 
     // Update only
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
-
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
-
-    artTagData: wikiData({
-      class: input.value(ArtTag),
-    }),
-
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
-    trackData: wikiData({
-      class: input.value(Track),
+    // used for referencedArtworkList (mixedFind)
+    artworkData: wikiData({
+      class: input.value(Artwork),
     }),
 
+    // used for withMatchingContributionPresets (indirectly by Contribution)
     wikiInfo: thing({
       class: input.value(WikiInfo),
     }),
@@ -298,7 +313,11 @@ export class Album extends Thing {
 
     commentatorArtists: commentatorArtists(),
 
-    hasCoverArt: contribsPresent({contribs: 'coverArtistContribs'}),
+    hasCoverArt: [
+      withHasCoverArt(),
+      exposeDependency({dependency: '#hasCoverArt'}),
+    ],
+
     hasWallpaperArt: contribsPresent({contribs: 'wallpaperArtistContribs'}),
     hasBannerArt: contribsPresent({contribs: 'bannerArtistContribs'}),
 
@@ -306,15 +325,6 @@ export class Album extends Thing {
       withTracks(),
       exposeDependency({dependency: '#tracks'}),
     ],
-
-    referencedByArtworks: [
-      exitWithoutContribs({
-        contribs: 'coverArtistContribs',
-        value: input.value([]),
-      }),
-
-      reverseReferencedArtworkList(),
-    ],
   });
 
   static [Thing.getSerializeDescriptors] = ({
@@ -359,16 +369,110 @@ export class Album extends Thing {
 
   static [Thing.findSpecs] = {
     album: {
-      referenceTypes: ['album', 'album-commentary', 'album-gallery'],
+      referenceTypes: [
+        'album',
+        'album-commentary',
+        'album-gallery',
+      ],
+
       bindTo: 'albumData',
+
+      getMatchableNames: album =>
+        (album.alwaysReferenceByDirectory 
+          ? [] 
+          : [album.name]),
     },
 
     albumWithArtwork: {
-      referenceTypes: ['album'],
+      referenceTypes: [
+        'album',
+        'album-referencing-artworks',
+        'album-referenced-artworks',
+      ],
+
       bindTo: 'albumData',
 
       include: album =>
         album.hasCoverArt,
+
+      getMatchableNames: album =>
+        (album.alwaysReferenceByDirectory 
+          ? [] 
+          : [album.name]),
+    },
+
+    albumPrimaryArtwork: {
+      [Thing.findThisThingOnly]: false,
+
+      referenceTypes: [
+        'album',
+        'album-referencing-artworks',
+        'album-referenced-artworks',
+      ],
+
+      bindTo: 'artworkData',
+
+      include: (artwork, {Artwork, Album}) =>
+        artwork instanceof Artwork &&
+        artwork.thing instanceof Album &&
+        artwork === artwork.thing.coverArtworks[0],
+
+      getMatchableNames: ({thing: album}) =>
+        (album.alwaysReferenceByDirectory
+          ? []
+          : [album.name]),
+
+      getMatchableDirectories: ({thing: album}) =>
+        [album.directory],
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    albumsWhoseTracksInclude: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.tracks,
+    },
+
+    albumsWhoseTrackSectionsInclude: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.trackSections,
+    },
+
+    albumsWhoseArtworksFeature: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.artTags,
+    },
+
+    albumsWhoseGroupsInclude: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.groups,
+    },
+
+    albumArtistContributionsBy:
+      soupyReverse.contributionsBy('albumData', 'artistContribs'),
+
+    albumCoverArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('albumData', 'coverArtworks'),
+
+    albumWallpaperArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('albumData', 'wallpaperArtwork', {single: true}),
+
+    albumBannerArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('albumData', 'bannerArtwork', {single: true}),
+
+    albumsWithCommentaryBy: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.commentatorArtists,
     },
   };
 
@@ -380,6 +484,7 @@ export class Album extends Thing {
       'Directory Suffix': {property: 'directorySuffix'},
       'Suffix Track Directories': {property: 'suffixTrackDirectories'},
 
+      'Always Reference By Directory': {property: 'alwaysReferenceByDirectory'},
       'Always Reference Tracks By Directory': {
         property: 'alwaysReferenceTracksByDirectory',
       },
@@ -399,6 +504,8 @@ export class Album extends Thing {
         transform: String,
       },
 
+      'Count Tracks In Artist Totals': {property: 'countInArtistTotals'},
+
       'Date': {
         property: 'date',
         transform: parseDate,
@@ -411,6 +518,49 @@ export class Album extends Thing {
       'Listed on Homepage': {property: 'isListedOnHomepage'},
       'Listed in Galleries': {property: 'isListedInGalleries'},
 
+      'Cover Artwork': {
+        property: 'coverArtworks',
+        transform:
+          parseArtwork({
+            thingProperty: 'coverArtworks',
+            dimensionsFromThingProperty: 'coverArtDimensions',
+            fileExtensionFromThingProperty: 'coverArtFileExtension',
+            dateFromThingProperty: 'coverArtDate',
+            artistContribsFromThingProperty: 'coverArtistContribs',
+            artistContribsArtistProperty: 'albumCoverArtistContributions',
+            artTagsFromThingProperty: 'artTags',
+            referencedArtworksFromThingProperty: 'referencedArtworks',
+          }),
+      },
+
+      'Banner Artwork': {
+        property: 'bannerArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            thingProperty: 'bannerArtwork',
+            dimensionsFromThingProperty: 'bannerDimensions',
+            fileExtensionFromThingProperty: 'bannerFileExtension',
+            dateFromThingProperty: 'date',
+            artistContribsFromThingProperty: 'bannerArtistContribs',
+            artistContribsArtistProperty: 'albumBannerArtistContributions',
+          }),
+      },
+
+      'Wallpaper Artwork': {
+        property: 'wallpaperArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            thingProperty: 'wallpaperArtwork',
+            dimensionsFromThingProperty: null,
+            fileExtensionFromThingProperty: 'wallpaperFileExtension',
+            dateFromThingProperty: 'date',
+            artistContribsFromThingProperty: 'wallpaperArtistContribs',
+            artistContribsArtistProperty: 'albumWallpaperArtistContributions',
+          }),
+      },
+
       'Cover Art Date': {
         property: 'coverArtDate',
         transform: parseDate,
@@ -444,9 +594,10 @@ export class Album extends Thing {
         transform: parseContributors,
       },
 
-      'Wallpaper Style': {property: 'wallpaperStyle'},
       'Wallpaper File Extension': {property: 'wallpaperFileExtension'},
 
+      'Wallpaper Style': {property: 'wallpaperStyle'},
+
       'Wallpaper Parts': {
         property: 'wallpaperParts',
         transform: parseWallpaperParts,
@@ -465,8 +616,15 @@ export class Album extends Thing {
         transform: parseDimensions,
       },
 
-      'Commentary': {property: 'commentary'},
-      'Credit Sources': {property: 'creditSources'},
+      'Commentary': {
+        property: 'commentary',
+        transform: parseCommentary,
+      },
+
+      'Crediting Sources': {
+        property: 'creditingSources',
+        transform: parseCreditingSources,
+      },
 
       'Additional Files': {
         property: 'additionalFiles',
@@ -516,7 +674,7 @@ export class Album extends Thing {
 
   static [Thing.getYamlLoadingSpec] = ({
     documentModes: {headerAndEntries},
-    thingConstructors: {Album, Track, TrackSectionHelper},
+    thingConstructors: {Album, Track},
   }) => ({
     title: `Process album files`,
 
@@ -538,6 +696,12 @@ export class Album extends Thing {
       const trackSectionData = [];
       const trackData = [];
 
+      const artworkData = [];
+      const commentaryData = [];
+      const creditingSourceData = [];
+      const referencingSourceData = [];
+      const lyricsData = [];
+
       for (const {header: album, entries} of results) {
         const trackSections = [];
 
@@ -549,8 +713,6 @@ export class Album extends Thing {
           isDefaultTrackSection: true,
         });
 
-        const albumRef = Thing.getReference(album);
-
         const closeCurrentTrackSection = () => {
           if (
             currentTrackSection.isDefaultTrackSection &&
@@ -577,17 +739,53 @@ export class Album extends Thing {
           currentTrackSectionTracks.push(entry);
           trackData.push(entry);
 
-          entry.dataSourceAlbum = albumRef;
+          // Set the track's album before accessing its list of artworks.
+          // The existence of its artwork objects may depend on access to
+          // its album's 'Default Track Cover Artists'.
+          entry.album = album;
+
+          artworkData.push(...entry.trackArtworks);
+          commentaryData.push(...entry.commentary);
+          creditingSourceData.push(...entry.creditingSources);
+          referencingSourceData.push(...entry.referencingSources);
+
+          // TODO: As exposed, Track.lyrics tries to inherit from the main
+          // release, which is impossible before the data's been linked.
+          // We just use the update value here. But it's icky!
+          lyricsData.push(...CacheableObject.getUpdateValue(entry, 'lyrics') ?? []);
         }
 
         closeCurrentTrackSection();
 
         albumData.push(album);
 
+        artworkData.push(...album.coverArtworks);
+
+        if (album.bannerArtwork) {
+          artworkData.push(album.bannerArtwork);
+        }
+
+        if (album.wallpaperArtwork) {
+          artworkData.push(album.wallpaperArtwork);
+        }
+
+        commentaryData.push(...album.commentary);
+        creditingSourceData.push(...album.creditingSources);
+
         album.trackSections = trackSections;
       }
 
-      return {albumData, trackSectionData, trackData};
+      return {
+        albumData,
+        trackSectionData,
+        trackData,
+
+        artworkData,
+        commentaryData,
+        creditingSourceData,
+        referencingSourceData,
+        lyricsData,
+      };
     },
 
     sort({albumData, trackData}) {
@@ -595,13 +793,65 @@ export class Album extends Thing {
       sortAlbumsTracksChronologically(trackData);
     },
   });
+
+  getOwnAdditionalFilePath(_file, filename) {
+    return [
+      'media.albumAdditionalFile',
+      this.directory,
+      filename,
+    ];
+  }
+
+  getOwnArtworkPath(artwork) {
+    if (artwork === this.bannerArtwork) {
+      return [
+        'media.albumBanner',
+        this.directory,
+        artwork.fileExtension,
+      ];
+    }
+
+    if (artwork === this.wallpaperArtwork) {
+      if (!empty(this.wallpaperParts)) {
+        return null;
+      }
+
+      return [
+        'media.albumWallpaper',
+        this.directory,
+        artwork.fileExtension,
+      ];
+    }
+
+    // TODO: using trackCover here is obviously, badly wrong
+    // but we ought to refactor banners and wallpapers similarly
+    // (i.e. depend on those intrinsic artwork paths rather than
+    // accessing media.{albumBanner,albumWallpaper} from content
+    // or other code directly)
+    return [
+      'media.trackCover',
+      this.directory,
+
+      (artwork.unqualifiedDirectory
+        ? 'cover-' + artwork.unqualifiedDirectory
+        : 'cover'),
+
+      artwork.fileExtension,
+    ];
+  }
+
+  // As of writing, albums don't even have a `duration` property...
+  // so this function will never be called... but the message stands...
+  countOwnContributionInDurationTotals(_contrib) {
+    return false;
+  }
 }
 
 export class TrackSection extends Thing {
   static [Thing.friendlyName] = `Track Section`;
   static [Thing.referenceType] = `track-section`;
 
-  static [Thing.getPropertyDescriptors] = ({Album, Track}) => ({
+  static [Thing.getPropertyDescriptors] = ({Track}) => ({
     // Update & expose
 
     name: name('Unnamed Track Section'),
@@ -623,6 +873,14 @@ export class TrackSection extends Thing {
       exposeDependency({dependency: '#album.color'}),
     ],
 
+    startCountingFrom: [
+      withStartCountingFrom({
+        from: input.updateValue({validate: isNumber}),
+      }),
+
+      exposeDependency({dependency: '#startCountingFrom'}),
+    ],
+
     dateOriginallyReleased: simpleDate(),
 
     isDefaultTrackSection: flag(false),
@@ -640,9 +898,7 @@ export class TrackSection extends Thing {
 
     // Update only
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
+    reverse: soupyReverse(),
 
     // Expose only
 
@@ -674,42 +930,10 @@ export class TrackSection extends Thing {
       },
     ],
 
-    startIndex: [
-      withAlbum(),
-
-      withPropertyFromObject({
-        object: '#album',
-        property: input.value('trackSections'),
-      }),
-
-      {
-        dependencies: ['#album.trackSections', input.myself()],
-        compute: (continuation, {
-          ['#album.trackSections']: trackSections,
-          [input.myself()]: myself,
-        }) => continuation({
-          ['#index']:
-            trackSections.indexOf(myself),
-        }),
-      },
-
-      exitWithoutDependency({
-        dependency: '#index',
-        mode: input.value('index'),
-        value: input.value(0),
-      }),
+    continueCountingFrom: [
+      withContinueCountingFrom(),
 
-      {
-        dependencies: ['#album.trackSections', '#index'],
-        compute: ({
-          ['#album.trackSections']: trackSections,
-          ['#index']: index,
-        }) =>
-          accumulateSum(
-            trackSections
-              .slice(0, index)
-              .map(section => section.tracks.length)),
-      },
+      exposeDependency({dependency: '#continueCountingFrom'}),
     ],
   });
 
@@ -727,10 +951,20 @@ export class TrackSection extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    trackSectionsWhichInclude: {
+      bindTo: 'trackSectionData',
+
+      referencing: trackSection => [trackSection],
+      referenced: trackSection => trackSection.tracks,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Section': {property: 'name'},
       'Color': {property: 'color'},
+      'Start Counting From': {property: 'startCountingFrom'},
 
       'Date Originally Released': {
         property: 'dateOriginallyReleased',
@@ -746,38 +980,38 @@ export class TrackSection extends Thing {
 
     parts.push(Thing.prototype[inspect.custom].apply(this));
 
-    if (depth >= 0) {
+    if (depth >= 0) showAlbum: {
       let album = null;
       try {
         album = this.album;
-      } catch {}
+      } catch {
+        break showAlbum;
+      }
 
       let first = null;
       try {
-        first = this.startIndex;
+        first = this.tracks.at(0).trackNumber;
       } catch {}
 
-      let length = null;
+      let last = null;
       try {
-        length = this.tracks.length;
+        last = this.tracks.at(-1).trackNumber;
       } catch {}
 
-      if (album) {
-        const albumName = album.name;
-        const albumIndex = album.trackSections.indexOf(this);
+      const albumName = album.name;
+      const albumIndex = album.trackSections.indexOf(this);
 
-        const num =
-          (albumIndex === -1
-            ? 'indeterminate position'
-            : `#${albumIndex + 1}`);
+      const num =
+        (albumIndex === -1
+          ? 'indeterminate position'
+          : `#${albumIndex + 1}`);
 
-        const range =
-          (albumIndex >= 0 && first !== null && length !== null
-            ? `: ${first + 1}-${first + length + 1}`
-            : '');
+      const range =
+        (albumIndex >= 0 && first !== null && last !== null
+          ? `: ${first}-${last}`
+          : '');
 
-        parts.push(` (${colors.yellow(num + range)} in ${colors.green(albumName)})`);
-      }
+      parts.push(` (${colors.yellow(num + range)} in ${colors.green(`"${albumName}"`)})`);
     }
 
     return parts.join('');
diff --git a/src/data/things/art-tag.js b/src/data/things/art-tag.js
index 3149b310..518f616b 100644
--- a/src/data/things/art-tag.js
+++ b/src/data/things/art-tag.js
@@ -1,31 +1,45 @@
 export const ART_TAG_DATA_FILE = 'tags.yaml';
 
 import {input} from '#composite';
-import {sortAlphabetically, sortAlbumsTracksChronologically} from '#sort';
+import {sortAlphabetically} from '#sort';
 import Thing from '#thing';
+import {unique} from '#sugar';
 import {isName} from '#validators';
+import {parseAdditionalNames, parseAnnotatedReferences} from '#yaml';
 
-import {exposeUpdateValueOrContinue} from '#composite/control-flow';
+import {exitWithoutDependency, exposeDependency, exposeUpdateValueOrContinue}
+  from '#composite/control-flow';
 
 import {
+  annotatedReferenceList,
   color,
+  contentString,
   directory,
   flag,
+  referenceList,
+  reverseReferenceList,
   name,
-  wikiData,
+  soupyFind,
+  soupyReverse,
+  thingList,
+  urls,
 } from '#composite/wiki-properties';
 
+import {withAllDescendantArtTags, withAncestorArtTagBaobabTree}
+  from '#composite/things/art-tag';
+
 export class ArtTag extends Thing {
   static [Thing.referenceType] = 'tag';
   static [Thing.friendlyName] = `Art Tag`;
 
-  static [Thing.getPropertyDescriptors] = ({Album, Track}) => ({
+  static [Thing.getPropertyDescriptors] = ({AdditionalName}) => ({
     // Update & expose
 
     name: name('Unnamed Art Tag'),
     directory: directory(),
     color: color(),
     isContentWarning: flag(false),
+    extraReadingURLs: urls(),
 
     nameShort: [
       exposeUpdateValueOrContinue({
@@ -39,30 +53,74 @@ export class ArtTag extends Thing {
       },
     ],
 
-    // Update only
+    additionalNames: thingList({
+      class: input.value(AdditionalName),
+    }),
 
-    albumData: wikiData({
-      class: input.value(Album),
+    description: contentString(),
+
+    directDescendantArtTags: referenceList({
+      class: input.value(ArtTag),
+      find: soupyFind.input('artTag'),
     }),
 
-    trackData: wikiData({
-      class: input.value(Track),
+    relatedArtTags: annotatedReferenceList({
+      class: input.value(ArtTag),
+      find: soupyFind.input('artTag'),
+
+      reference: input.value('artTag'),
+      thing: input.value('artTag'),
     }),
 
+    // Update only
+
+    find: soupyFind(),
+    reverse: soupyReverse(),
+
     // Expose only
 
-    taggedInThings: {
-      flags: {expose: true},
+    descriptionShort: [
+      exitWithoutDependency({
+        dependency: 'description',
+        mode: input.value('falsy'),
+      }),
+
+      {
+        dependencies: ['description'],
+        compute: ({description}) =>
+          description.split('<hr class="split">')[0],
+      },
+    ],
 
-      expose: {
-        dependencies: ['this', 'albumData', 'trackData'],
-        compute: ({this: artTag, albumData, trackData}) =>
-          sortAlbumsTracksChronologically(
-            [...albumData, ...trackData]
-              .filter(({artTags}) => artTags.includes(artTag)),
-            {getDate: thing => thing.coverArtDate ?? thing.date}),
+    directlyFeaturedInArtworks: reverseReferenceList({
+      reverse: soupyReverse.input('artworksWhichFeature'),
+    }),
+
+    indirectlyFeaturedInArtworks: [
+      withAllDescendantArtTags(),
+
+      {
+        dependencies: ['#allDescendantArtTags'],
+        compute: ({'#allDescendantArtTags': allDescendantArtTags}) =>
+          unique(
+            allDescendantArtTags
+              .flatMap(artTag => artTag.directlyFeaturedInArtworks)),
       },
-    },
+    ],
+
+    allDescendantArtTags: [
+      withAllDescendantArtTags(),
+      exposeDependency({dependency: '#allDescendantArtTags'}),
+    ],
+
+    directAncestorArtTags: reverseReferenceList({
+      reverse: soupyReverse.input('artTagsWhichDirectlyAncestor'),
+    }),
+
+    ancestorArtTagBaobabTree: [
+      withAncestorArtTagBaobabTree(),
+      exposeDependency({dependency: '#ancestorArtTagBaobabTree'}),
+    ],
   });
 
   static [Thing.findSpecs] = {
@@ -70,10 +128,19 @@ export class ArtTag extends Thing {
       referenceTypes: ['tag'],
       bindTo: 'artTagData',
 
-      getMatchableNames: tag =>
-        (tag.isContentWarning
-          ? [`cw: ${tag.name}`]
-          : [tag.name]),
+      getMatchableNames: artTag =>
+        (artTag.isContentWarning
+          ? [`cw: ${artTag.name}`]
+          : [artTag.name]),
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    artTagsWhichDirectlyAncestor: {
+      bindTo: 'artTagData',
+
+      referencing: artTag => [artTag],
+      referenced: artTag => artTag.directDescendantArtTags,
     },
   };
 
@@ -82,9 +149,27 @@ export class ArtTag extends Thing {
       'Tag': {property: 'name'},
       'Short Name': {property: 'nameShort'},
       'Directory': {property: 'directory'},
+      'Description': {property: 'description'},
+      'Extra Reading URLs': {property: 'extraReadingURLs'},
+
+      'Additional Names': {
+        property: 'additionalNames',
+        transform: parseAdditionalNames,
+      },
 
       'Color': {property: 'color'},
       'Is CW': {property: 'isContentWarning'},
+
+      'Direct Descendant Tags': {property: 'directDescendantArtTags'},
+
+      'Related Tags': {
+        property: 'relatedArtTags',
+        transform: entries =>
+          parseAnnotatedReferences(entries, {
+            referenceField: 'Tag',
+            referenceProperty: 'artTag',
+          }),
+      },
     },
   };
 
diff --git a/src/data/things/artist.js b/src/data/things/artist.js
index 8fdb8a12..5b67051c 100644
--- a/src/data/things/artist.js
+++ b/src/data/things/artist.js
@@ -5,28 +5,27 @@ import {inspect} from 'node:util';
 import CacheableObject from '#cacheable-object';
 import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import {sortAlphabetically} from '#sort';
-import {stitchArrays, unique} from '#sugar';
+import {stitchArrays} from '#sugar';
 import Thing from '#thing';
 import {isName, validateArrayItems} from '#validators';
 import {getKebabCase} from '#wiki-data';
+import {parseArtwork} from '#yaml';
 
-import {exposeDependency} from '#composite/control-flow';
-import {withReverseContributionList} from '#composite/wiki-data';
+import {exitWithoutDependency} from '#composite/control-flow';
 
 import {
+  constitutibleArtwork,
   contentString,
   directory,
   fileExtension,
   flag,
   name,
-  reverseAnnotatedReferenceList,
-  reverseContributionList,
   reverseReferenceList,
   singleReference,
+  soupyFind,
+  soupyReverse,
   urls,
-  wikiData,
 } from '#composite/wiki-properties';
 
 import {artistTotalDuration} from '#composite/things/artist';
@@ -35,7 +34,7 @@ export class Artist extends Thing {
   static [Thing.referenceType] = 'artist';
   static [Thing.wikiDataArray] = 'artistData';
 
-  static [Thing.getPropertyDescriptors] = ({Album, Flash, Group, Track}) => ({
+  static [Thing.getPropertyDescriptors] = () => ({
     // Update & expose
 
     name: name('Unnamed Artist'),
@@ -47,6 +46,16 @@ export class Artist extends Thing {
     hasAvatar: flag(false),
     avatarFileExtension: fileExtension('jpg'),
 
+    avatarArtwork: [
+      exitWithoutDependency({
+        dependency: 'hasAvatar',
+        value: input.value(null),
+      }),
+
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Avatar Artwork'),
+    ],
+
     aliasNames: {
       flags: {update: true, expose: true},
       update: {validate: validateArrayItems(isName)},
@@ -57,95 +66,62 @@ export class Artist extends Thing {
 
     aliasedArtist: singleReference({
       class: input.value(Artist),
-      find: input.value(find.artist),
-      data: 'artistData',
+      find: soupyFind.input('artist'),
     }),
 
     // Update only
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
-
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
-
-    flashData: wikiData({
-      class: input.value(Flash),
-    }),
-
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
-
-    trackData: wikiData({
-      class: input.value(Track),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
     // Expose only
 
-    trackArtistContributions: reverseContributionList({
-      data: 'trackData',
-      list: input.value('artistContribs'),
+    trackArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('trackArtistContributionsBy'),
     }),
 
-    trackContributorContributions: reverseContributionList({
-      data: 'trackData',
-      list: input.value('contributorContribs'),
+    trackContributorContributions: reverseReferenceList({
+      reverse: soupyReverse.input('trackContributorContributionsBy'),
     }),
 
-    trackCoverArtistContributions: reverseContributionList({
-      data: 'trackData',
-      list: input.value('coverArtistContribs'),
+    trackCoverArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('trackCoverArtistContributionsBy'),
     }),
 
     tracksAsCommentator: reverseReferenceList({
-      data: 'trackData',
-      list: input.value('commentatorArtists'),
+      reverse: soupyReverse.input('tracksWithCommentaryBy'),
     }),
 
-    albumArtistContributions: reverseContributionList({
-      data: 'albumData',
-      list: input.value('artistContribs'),
+    albumArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumArtistContributionsBy'),
     }),
 
-    albumCoverArtistContributions: reverseContributionList({
-      data: 'albumData',
-      list: input.value('coverArtistContribs'),
+    albumCoverArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumCoverArtistContributionsBy'),
     }),
 
-    albumWallpaperArtistContributions: reverseContributionList({
-      data: 'albumData',
-      list: input.value('wallpaperArtistContribs'),
+    albumWallpaperArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumWallpaperArtistContributionsBy'),
     }),
 
-    albumBannerArtistContributions: reverseContributionList({
-      data: 'albumData',
-      list: input.value('bannerArtistContribs'),
+    albumBannerArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumBannerArtistContributionsBy'),
     }),
 
     albumsAsCommentator: reverseReferenceList({
-      data: 'albumData',
-      list: input.value('commentatorArtists'),
+      reverse: soupyReverse.input('albumsWithCommentaryBy'),
     }),
 
-    flashContributorContributions: reverseContributionList({
-      data: 'flashData',
-      list: input.value('contributorContribs'),
+    flashContributorContributions: reverseReferenceList({
+      reverse: soupyReverse.input('flashContributorContributionsBy'),
     }),
 
     flashesAsCommentator: reverseReferenceList({
-      data: 'flashData',
-      list: input.value('commentatorArtists'),
+      reverse: soupyReverse.input('flashesWithCommentaryBy'),
     }),
 
-    closelyLinkedGroups: reverseAnnotatedReferenceList({
-      data: 'groupData',
-      list: input.value('closelyLinkedArtists'),
-
-      forward: input.value('artist'),
-      backward: input.value('group'),
+    closelyLinkedGroups: reverseReferenceList({
+      reverse: soupyReverse.input('groupsCloselyLinkedTo'),
     }),
 
     totalDuration: artistTotalDuration(),
@@ -230,6 +206,17 @@ export class Artist extends Thing {
       'URLs': {property: 'urls'},
       'Context Notes': {property: 'contextNotes'},
 
+      // note: doesn't really work as an independent field yet
+      'Avatar Artwork': {
+        property: 'avatarArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            thingProperty: 'avatarArtwork',
+            fileExtensionFromThingProperty: 'avatarFileExtension',
+          }),
+      },
+
       'Has Avatar': {property: 'hasAvatar'},
       'Avatar File Extension': {property: 'avatarFileExtension'},
 
@@ -275,7 +262,12 @@ export class Artist extends Thing {
 
       const artistData = [...artists, ...artistAliases];
 
-      return {artistData};
+      const artworkData =
+        artistData
+          .filter(artist => artist.hasAvatar)
+          .map(artist => artist.avatarArtwork);
+
+      return {artistData, artworkData};
     },
 
     sort({artistData}) {
@@ -294,7 +286,7 @@ export class Artist extends Thing {
       let aliasedArtist;
       try {
         aliasedArtist = this.aliasedArtist.name;
-      } catch (_error) {
+      } catch {
         aliasedArtist = CacheableObject.getUpdateValue(this, 'aliasedArtist');
       }
 
@@ -303,4 +295,12 @@ export class Artist extends Thing {
 
     return parts.join('');
   }
+
+  getOwnArtworkPath(artwork) {
+    return [
+      'media.artistAvatar',
+      this.directory,
+      artwork.fileExtension,
+    ];
+  }
 }
diff --git a/src/data/things/artwork.js b/src/data/things/artwork.js
new file mode 100644
index 00000000..57c293ca
--- /dev/null
+++ b/src/data/things/artwork.js
@@ -0,0 +1,510 @@
+import {inspect} from 'node:util';
+
+import {colors} from '#cli';
+import {input} from '#composite';
+import find from '#find';
+import Thing from '#thing';
+
+import {
+  isContentString,
+  isContributionList,
+  isDate,
+  isDimensions,
+  isFileExtension,
+  optional,
+  validateArrayItems,
+  validateProperties,
+  validateReference,
+  validateReferenceList,
+} from '#validators';
+
+import {
+  parseAnnotatedReferences,
+  parseContributors,
+  parseDate,
+  parseDimensions,
+} from '#yaml';
+
+import {withPropertyFromObject} from '#composite/data';
+
+import {
+  exitWithoutDependency,
+  exposeConstant,
+  exposeDependency,
+  exposeDependencyOrContinue,
+  exposeUpdateValueOrContinue,
+} from '#composite/control-flow';
+
+import {
+  withRecontextualizedContributionList,
+  withResolvedAnnotatedReferenceList,
+  withResolvedContribs,
+  withResolvedReferenceList,
+} from '#composite/wiki-data';
+
+import {
+  contentString,
+  directory,
+  flag,
+  reverseReferenceList,
+  simpleString,
+  soupyFind,
+  soupyReverse,
+  thing,
+  wikiData,
+} from '#composite/wiki-properties';
+
+import {
+  withAttachedArtwork,
+  withContainingArtworkList,
+  withContribsFromAttachedArtwork,
+  withPropertyFromAttachedArtwork,
+  withDate,
+} from '#composite/things/artwork';
+
+export class Artwork extends Thing {
+  static [Thing.referenceType] = 'artwork';
+
+  static [Thing.getPropertyDescriptors] = ({ArtTag}) => ({
+    // Update & expose
+
+    unqualifiedDirectory: directory({
+      name: input.value(null),
+    }),
+
+    thing: thing(),
+    thingProperty: simpleString(),
+
+    label: simpleString(),
+    source: contentString(),
+    originDetails: contentString(),
+
+    dateFromThingProperty: simpleString(),
+
+    date: [
+      withDate({
+        from: input.updateValue({validate: isDate}),
+      }),
+
+      exposeDependency({dependency: '#date'}),
+    ],
+
+    fileExtensionFromThingProperty: simpleString(),
+
+    fileExtension: [
+      {
+        compute: (continuation) => continuation({
+          ['#default']: 'jpg',
+        }),
+      },
+
+      exposeUpdateValueOrContinue({
+        validate: input.value(isFileExtension),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'thing',
+        value: '#default',
+      }),
+
+      exitWithoutDependency({
+        dependency: 'fileExtensionFromThingProperty',
+        value: '#default',
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'fileExtensionFromThingProperty',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#value',
+      }),
+
+      exposeDependency({
+        dependency: '#default',
+      }),
+    ],
+
+    dimensionsFromThingProperty: simpleString(),
+
+    dimensions: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(isDimensions),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'dimensionsFromThingProperty',
+        value: input.value(null),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'dimensionsFromThingProperty',
+      }).outputs({
+        ['#value']: '#dimensionsFromThing',
+      }),
+
+      exitWithoutDependency({
+        dependency: 'dimensionsFromThingProperty',
+        value: input.value(null),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#dimensionsFromThing',
+      }),
+
+      exposeConstant({
+        value: input.value(null),
+      }),
+    ],
+
+    attachAbove: flag(false),
+
+    artistContribsFromThingProperty: simpleString(),
+    artistContribsArtistProperty: simpleString(),
+
+    artistContribs: [
+      withDate(),
+
+      withResolvedContribs({
+        from: input.updateValue({validate: isContributionList}),
+        date: '#date',
+        thingProperty: input.thisProperty(),
+        artistProperty: 'artistContribsArtistProperty',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#resolvedContribs',
+        mode: input.value('empty'),
+      }),
+
+      withContribsFromAttachedArtwork(),
+
+      exposeDependencyOrContinue({
+        dependency: '#attachedArtwork.artistContribs',
+      }),
+
+      exitWithoutDependency({
+        dependency: 'artistContribsFromThingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'artistContribsFromThingProperty',
+      }).outputs({
+        ['#value']: '#artistContribs',
+      }),
+
+      withRecontextualizedContributionList({
+        list: '#artistContribs',
+      }),
+
+      exposeDependency({
+        dependency: '#artistContribs',
+      }),
+    ],
+
+    artTagsFromThingProperty: simpleString(),
+
+    artTags: [
+      withResolvedReferenceList({
+        list: input.updateValue({
+          validate:
+            validateReferenceList(ArtTag[Thing.referenceType]),
+        }),
+
+        find: soupyFind.input('artTag'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#resolvedReferenceList',
+        mode: input.value('empty'),
+      }),
+
+      withPropertyFromAttachedArtwork({
+        property: input.value('artTags'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#attachedArtwork.artTags',
+      }),
+
+      exitWithoutDependency({
+        dependency: 'artTagsFromThingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'artTagsFromThingProperty',
+      }).outputs({
+        ['#value']: '#artTags',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#artTags',
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
+
+    referencedArtworksFromThingProperty: simpleString(),
+
+    referencedArtworks: [
+      {
+        compute: (continuation) => continuation({
+          ['#find']:
+            find.mixed({
+              track: find.trackPrimaryArtwork,
+              album: find.albumPrimaryArtwork,
+            }),
+        }),
+      },
+
+      withResolvedAnnotatedReferenceList({
+        list: input.updateValue({
+          validate:
+            // TODO: It's annoying to hardcode this when it's really the
+            // same behavior as through annotatedReferenceList and through
+            // referenceListUpdateDescription, the latter of which isn't
+            // available outside of #composite/wiki-data internals.
+            validateArrayItems(
+              validateProperties({
+                reference: validateReference(['album', 'track']),
+                annotation: optional(isContentString),
+              })),
+        }),
+
+        data: 'artworkData',
+        find: '#find',
+
+        thing: input.value('artwork'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#resolvedAnnotatedReferenceList',
+        mode: input.value('empty'),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'referencedArtworksFromThingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'referencedArtworksFromThingProperty',
+      }).outputs({
+        ['#value']: '#referencedArtworks',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#referencedArtworks',
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
+
+    // Update only
+
+    find: soupyFind(),
+    reverse: soupyReverse(),
+
+    // used for referencedArtworks (mixedFind)
+    artworkData: wikiData({
+      class: input.value(Artwork),
+    }),
+
+    // Expose only
+
+    referencedByArtworks: reverseReferenceList({
+      reverse: soupyReverse.input('artworksWhichReference'),
+    }),
+
+    isMainArtwork: [
+      withContainingArtworkList(),
+
+      exitWithoutDependency({
+        dependency: '#containingArtworkList',
+        value: input.value(null),
+      }),
+
+      {
+        dependencies: [input.myself(), '#containingArtworkList'],
+        compute: ({
+          [input.myself()]: myself,
+          ['#containingArtworkList']: list,
+        }) =>
+          list[0] === myself,
+      },
+    ],
+
+    mainArtwork: [
+      withContainingArtworkList(),
+
+      exitWithoutDependency({
+        dependency: '#containingArtworkList',
+        value: input.value(null),
+      }),
+
+      {
+        dependencies: ['#containingArtworkList'],
+        compute: ({'#containingArtworkList': list}) =>
+          list[0],
+      },
+    ],
+
+    attachedArtwork: [
+      withAttachedArtwork(),
+
+      exposeDependency({
+        dependency: '#attachedArtwork',
+      }),
+    ],
+
+    attachingArtworks: reverseReferenceList({
+      reverse: soupyReverse.input('artworksWhichAttach'),
+    }),
+
+    groups: [
+      withPropertyFromObject({
+        object: 'thing',
+        property: input.value('groups'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#thing.groups',
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Directory': {property: 'unqualifiedDirectory'},
+      'File Extension': {property: 'fileExtension'},
+
+      'Dimensions': {
+        property: 'dimensions',
+        transform: parseDimensions,
+      },
+
+      'Label': {property: 'label'},
+      'Source': {property: 'source'},
+      'Origin Details': {property: 'originDetails'},
+
+      'Date': {
+        property: 'date',
+        transform: parseDate,
+      },
+
+      'Attach Above': {property: 'attachAbove'},
+
+      'Artists': {
+        property: 'artistContribs',
+        transform: parseContributors,
+      },
+
+      'Tags': {property: 'artTags'},
+
+      'Referenced Artworks': {
+        property: 'referencedArtworks',
+        transform: parseAnnotatedReferences,
+      },
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    artworksWhichReference: {
+      bindTo: 'artworkData',
+
+      referencing: referencingArtwork =>
+        referencingArtwork.referencedArtworks
+          .map(({artwork: referencedArtwork, ...referenceDetails}) => ({
+            referencingArtwork,
+            referencedArtwork,
+            referenceDetails,
+          })),
+
+      referenced: ({referencedArtwork}) => [referencedArtwork],
+
+      tidy: ({referencingArtwork, referenceDetails}) => ({
+        artwork: referencingArtwork,
+        ...referenceDetails,
+      }),
+
+      date: ({artwork}) => artwork.date,
+    },
+
+    artworksWhichAttach: {
+      bindTo: 'artworkData',
+
+      referencing: referencingArtwork =>
+        (referencingArtwork.attachAbove
+          ? [referencingArtwork]
+          : []),
+
+      referenced: referencingArtwork =>
+        [referencingArtwork.attachedArtwork],
+    },
+
+    artworksWhichFeature: {
+      bindTo: 'artworkData',
+
+      referencing: artwork => [artwork],
+      referenced: artwork => artwork.artTags,
+    },
+  };
+
+  get path() {
+    if (!this.thing) return null;
+    if (!this.thing.getOwnArtworkPath) return null;
+
+    return this.thing.getOwnArtworkPath(this);
+  }
+
+  countOwnContributionInContributionTotals(contrib) {
+    if (this.attachAbove) {
+      return false;
+    }
+
+    if (contrib.annotation?.startsWith('edits for wiki')) {
+      return false;
+    }
+
+    return true;
+  }
+
+  [inspect.custom](depth, options, inspect) {
+    const parts = [];
+
+    parts.push(Thing.prototype[inspect.custom].apply(this));
+
+    if (this.thing) {
+      if (depth >= 0) {
+        const newOptions = {
+          ...options,
+          depth:
+            (options.depth === null
+              ? null
+              : options.depth - 1),
+        };
+
+        parts.push(` for ${inspect(this.thing, newOptions)}`);
+      } else {
+        parts.push(` for ${colors.blue(Thing.getReference(this.thing))}`);
+      }
+    }
+
+    return parts.join('');
+  }
+}
diff --git a/src/data/things/content.js b/src/data/things/content.js
new file mode 100644
index 00000000..ca41ccaa
--- /dev/null
+++ b/src/data/things/content.js
@@ -0,0 +1,205 @@
+import {input} from '#composite';
+import Thing from '#thing';
+import {is, isDate} from '#validators';
+import {parseDate} from '#yaml';
+
+import {contentString, simpleDate, soupyFind, thing}
+  from '#composite/wiki-properties';
+
+import {
+  exitWithoutDependency,
+  exposeConstant,
+  exposeDependency,
+  exposeDependencyOrContinue,
+  exposeUpdateValueOrContinue,
+  withResultOfAvailabilityCheck,
+} from '#composite/control-flow';
+
+import {
+  contentArtists,
+  hasAnnotationPart,
+  withAnnotationParts,
+  withHasAnnotationPart,
+  withSourceText,
+  withSourceURLs,
+  withWebArchiveDate,
+} from '#composite/things/content';
+
+export class ContentEntry extends Thing {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    thing: thing(),
+
+    artists: contentArtists(),
+
+    artistText: contentString(),
+
+    annotation: contentString(),
+
+    dateKind: {
+      flags: {update: true, expose: true},
+
+      update: {
+        validate: is(...[
+          'sometime',
+          'throughout',
+          'around',
+        ]),
+      },
+    },
+
+    accessKind: [
+      exitWithoutDependency({
+        dependency: 'accessDate',
+      }),
+
+      exposeUpdateValueOrContinue({
+        validate: input.value(
+          is(...[
+            'captured',
+            'accessed',
+          ])),
+      }),
+
+      withWebArchiveDate(),
+
+      withResultOfAvailabilityCheck({
+        from: '#webArchiveDate',
+      }),
+
+      {
+        dependencies: ['#availability'],
+        compute: (continuation, {['#availability']: availability}) =>
+          (availability
+            ? continuation.exit('captured')
+            : continuation()),
+      },
+
+      exposeConstant({
+        value: input.value('accessed'),
+      }),
+    ],
+
+    date: simpleDate(),
+
+    secondDate: simpleDate(),
+
+    accessDate: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(isDate),
+      }),
+
+      withWebArchiveDate(),
+
+      exposeDependencyOrContinue({
+        dependency: '#webArchiveDate',
+      }),
+
+      exposeConstant({
+        value: input.value(null),
+      }),
+    ],
+
+    body: contentString(),
+
+    // Update only
+
+    find: soupyFind(),
+
+    // Expose only
+
+    annotationParts: [
+      withAnnotationParts({
+        mode: input.value('strings'),
+      }),
+
+      exposeDependency({dependency: '#annotationParts'}),
+    ],
+
+    sourceText: [
+      withSourceText(),
+      exposeDependency({dependency: '#sourceText'}),
+    ],
+
+    sourceURLs: [
+      withSourceURLs(),
+      exposeDependency({dependency: '#sourceURLs'}),
+    ],
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Artists': {property: 'artists'},
+      'Artist Text': {property: 'artistText'},
+
+      'Annotation': {property: 'annotation'},
+
+      'Date Kind': {property: 'dateKind'},
+      'Access Kind': {property: 'accessKind'},
+
+      'Date': {property: 'date', transform: parseDate},
+      'Second Date': {property: 'secondDate', transform: parseDate},
+      'Access Date': {property: 'accessDate', transform: parseDate},
+
+      'Body': {property: 'body'},
+    },
+  };
+}
+
+export class CommentaryEntry extends ContentEntry {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Expose only
+
+    isWikiEditorCommentary: hasAnnotationPart({
+      part: input.value('wiki editor'),
+    }),
+  });
+}
+
+export class LyricsEntry extends ContentEntry {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    originDetails: contentString(),
+
+    // Expose only
+
+    isWikiLyrics: hasAnnotationPart({
+      part: input.value('wiki lyrics'),
+    }),
+
+    hasSquareBracketAnnotations: [
+      withHasAnnotationPart({
+        part: input.value('wiki lyrics'),
+      }),
+
+      exitWithoutDependency({
+        dependency: '#hasAnnotationPart',
+        mode: input.value('falsy'),
+        value: input.value(false),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'body',
+        value: input.value(false),
+      }),
+
+      {
+        dependencies: ['body'],
+        compute: ({body}) =>
+          /\[.*\]/m.test(body),
+      },
+    ],
+  });
+
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(ContentEntry, {
+    fields: {
+      'Origin Details': {property: 'originDetails'},
+    },
+  });
+}
+
+export class CreditingSourcesEntry extends ContentEntry {}
+
+export class ReferencingSourcesEntry extends ContentEntry {}
diff --git a/src/data/things/contribution.js b/src/data/things/contribution.js
index 2712af70..90e8eb79 100644
--- a/src/data/things/contribution.js
+++ b/src/data/things/contribution.js
@@ -5,11 +5,18 @@ import {colors} from '#cli';
 import {input} from '#composite';
 import {empty} from '#sugar';
 import Thing from '#thing';
-import {isStringNonEmpty, isThing, validateReference} from '#validators';
+import {isBoolean, isStringNonEmpty, isThing, validateReference}
+  from '#validators';
 
-import {exitWithoutDependency, exposeDependency} from '#composite/control-flow';
-import {withResolvedReference} from '#composite/wiki-data';
-import {flag, simpleDate} from '#composite/wiki-properties';
+import {flag, simpleDate, soupyFind} from '#composite/wiki-properties';
+
+import {
+  exitWithoutDependency,
+  exposeConstant,
+  exposeDependency,
+  exposeDependencyOrContinue,
+  exposeUpdateValueOrContinue,
+} from '#composite/control-flow';
 
 import {
   withFilteredList,
@@ -71,7 +78,26 @@ export class Contribution extends Thing {
         property: input.thisProperty(),
       }),
 
-      flag(true),
+      exposeUpdateValueOrContinue({
+        validate: input.value(isBoolean),
+      }),
+
+      {
+        dependencies: ['thing', input.myself()],
+        compute: (continuation, {
+          ['thing']: thing,
+          [input.myself()]: contribution,
+        }) =>
+          (thing.countOwnContributionInContributionTotals?.(contribution)
+            ? true
+         : thing.countOwnContributionInContributionTotals
+            ? false
+            : continuation()),
+      },
+
+      exposeConstant({
+        value: input.value(true),
+      }),
     ],
 
     countInDurationTotals: [
@@ -79,9 +105,43 @@ export class Contribution extends Thing {
         property: input.thisProperty(),
       }),
 
-      flag(true),
+      exposeUpdateValueOrContinue({
+        validate: input.value(isBoolean),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: input.value('duration'),
+      }),
+
+      exitWithoutDependency({
+        dependency: '#thing.duration',
+        mode: input.value('falsy'),
+        value: input.value(false),
+      }),
+
+      {
+        dependencies: ['thing', input.myself()],
+        compute: (continuation, {
+          ['thing']: thing,
+          [input.myself()]: contribution,
+        }) =>
+          (thing.countOwnContributionInDurationTotals?.(contribution)
+            ? true
+         : thing.countOwnContributionInDurationTotals
+            ? false
+            : continuation()),
+      },
+
+      exposeConstant({
+        value: input.value(true),
+      }),
     ],
 
+    // Update only
+
+    find: soupyFind(),
+
     // Expose only
 
     context: [
@@ -235,6 +295,21 @@ export class Contribution extends Thing {
         dependency: '#nearbyItem',
       }),
     ],
+
+    groups: [
+      withPropertyFromObject({
+        object: 'thing',
+        property: input.value('groups'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#thing.groups',
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
   });
 
   [inspect.custom](depth, options, inspect) {
@@ -256,7 +331,7 @@ export class Contribution extends Thing {
       let artist;
       try {
         artist = this.artist;
-      } catch (_error) {
+      } catch {
         // Computing artist might crash for any reason - don't distract from
         // other errors as a result of inspecting this contribution.
       }
diff --git a/src/data/things/flash.js b/src/data/things/flash.js
index aa6b9cd1..160221f0 100644
--- a/src/data/things/flash.js
+++ b/src/data/things/flash.js
@@ -1,13 +1,21 @@
 export const FLASH_DATA_FILE = 'flashes.yaml';
 
 import {input} from '#composite';
-import find from '#find';
 import {empty} from '#sugar';
 import {sortFlashesChronologically} from '#sort';
 import Thing from '#thing';
 import {anyOf, isColor, isContentString, isDirectory, isNumber, isString}
   from '#validators';
-import {parseContributors, parseDate, parseDimensions} from '#yaml';
+
+import {
+  parseArtwork,
+  parseAdditionalNames,
+  parseCommentary,
+  parseContributors,
+  parseCreditingSources,
+  parseDate,
+  parseDimensions,
+} from '#yaml';
 
 import {withPropertyFromObject} from '#composite/data';
 
@@ -20,8 +28,8 @@ import {
 
 import {
   color,
-  commentary,
   commentatorArtists,
+  constitutibleArtwork,
   contentString,
   contributionList,
   dimensions,
@@ -30,9 +38,11 @@ import {
   name,
   referenceList,
   simpleDate,
+  soupyFind,
+  soupyReverse,
   thing,
+  thingList,
   urls,
-  wikiData,
 } from '#composite/wiki-properties';
 
 import {withFlashAct} from '#composite/things/flash';
@@ -42,9 +52,10 @@ export class Flash extends Thing {
   static [Thing.referenceType] = 'flash';
 
   static [Thing.getPropertyDescriptors] = ({
-    Artist,
+    AdditionalName,
+    CommentaryEntry,
+    CreditingSourcesEntry,
     Track,
-    FlashAct,
     WikiInfo,
   }) => ({
     // Update & expose
@@ -98,6 +109,10 @@ export class Flash extends Thing {
 
     coverArtDimensions: dimensions(),
 
+    coverArtwork:
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Cover Artwork'),
+
     contributorContribs: contributionList({
       date: 'date',
       artistProperty: input.value('flashContributorContributions'),
@@ -105,29 +120,29 @@ export class Flash extends Thing {
 
     featuredTracks: referenceList({
       class: input.value(Track),
-      find: input.value(find.track),
-      data: 'trackData',
+      find: soupyFind.input('track'),
     }),
 
     urls: urls(),
 
-    commentary: commentary(),
-    creditSources: commentary(),
-
-    // Update only
-
-    artistData: wikiData({
-      class: input.value(Artist),
+    additionalNames: thingList({
+      class: input.value(AdditionalName),
     }),
 
-    trackData: wikiData({
-      class: input.value(Track),
+    commentary: thingList({
+      class: input.value(CommentaryEntry),
     }),
 
-    flashActData: wikiData({
-      class: input.value(FlashAct),
+    creditingSources: thingList({
+      class: input.value(CreditingSourcesEntry),
     }),
 
+    // Update only
+
+    find: soupyFind(),
+    reverse: soupyReverse(),
+
+    // used for withMatchingContributionPresets (indirectly by Contribution)
     wikiInfo: thing({
       class: input.value(WikiInfo),
     }),
@@ -173,6 +188,25 @@ export class Flash extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    flashesWhichFeature: {
+      bindTo: 'flashData',
+
+      referencing: flash => [flash],
+      referenced: flash => flash.featuredTracks,
+    },
+
+    flashContributorContributionsBy:
+      soupyReverse.contributionsBy('flashData', 'contributorContribs'),
+
+    flashesWithCommentaryBy: {
+      bindTo: 'flashData',
+
+      referencing: flash => [flash],
+      referenced: flash => flash.commentatorArtists,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Flash': {property: 'name'},
@@ -186,6 +220,22 @@ export class Flash extends Thing {
         transform: parseDate,
       },
 
+      'Additional Names': {
+        property: 'additionalNames',
+        transform: parseAdditionalNames,
+      },
+
+      'Cover Artwork': {
+        property: 'coverArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            thingProperty: 'coverArtwork',
+            fileExtensionFromThingProperty: 'coverArtFileExtension',
+            dimensionsFromThingProperty: 'coverArtDimensions',
+          }),
+      },
+
       'Cover Art File Extension': {property: 'coverArtFileExtension'},
 
       'Cover Art Dimensions': {
@@ -200,12 +250,27 @@ export class Flash extends Thing {
         transform: parseContributors,
       },
 
-      'Commentary': {property: 'commentary'},
-      'Credit Sources': {property: 'creditSources'},
+      'Commentary': {
+        property: 'commentary',
+        transform: parseCommentary,
+      },
+
+      'Crediting Sources': {
+        property: 'creditingSources',
+        transform: parseCreditingSources,
+      },
 
       'Review Points': {ignore: true},
     },
   };
+
+  getOwnArtworkPath(artwork) {
+    return [
+      'media.flashArt',
+      this.directory,
+      artwork.fileExtension,
+    ];
+  }
 }
 
 export class FlashAct extends Thing {
@@ -242,19 +307,13 @@ export class FlashAct extends Thing {
 
     flashes: referenceList({
       class: input.value(Flash),
-      find: input.value(find.flash),
-      data: 'flashData',
+      find: soupyFind.input('flash'),
     }),
 
     // Update only
 
-    flashData: wikiData({
-      class: input.value(Flash),
-    }),
-
-    flashSideData: wikiData({
-      class: input.value(FlashSide),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
     // Expose only
 
@@ -271,6 +330,15 @@ export class FlashAct extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    flashActsWhoseFlashesInclude: {
+      bindTo: 'flashActData',
+
+      referencing: flashAct => [flashAct],
+      referenced: flashAct => flashAct.flashes,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Act': {property: 'name'},
@@ -298,15 +366,12 @@ export class FlashSide extends Thing {
 
     acts: referenceList({
       class: input.value(FlashAct),
-      find: input.value(find.flashAct),
-      data: 'flashActData',
+      find: soupyFind.input('flashAct'),
     }),
 
     // Update only
 
-    flashActData: wikiData({
-      class: input.value(FlashAct),
-    }),
+    find: soupyFind(),
   });
 
   static [Thing.yamlDocumentSpec] = {
@@ -325,6 +390,15 @@ export class FlashSide extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    flashSidesWhoseActsInclude: {
+      bindTo: 'flashSideData',
+
+      referencing: flashSide => [flashSide],
+      referenced: flashSide => flashSide.acts,
+    },
+  };
+
   static [Thing.getYamlLoadingSpec] = ({
     documentModes: {allInOne},
     thingConstructors: {Flash, FlashAct},
@@ -383,7 +457,19 @@ export class FlashSide extends Thing {
       const flashActData = results.filter(x => x instanceof FlashAct);
       const flashSideData = results.filter(x => x instanceof FlashSide);
 
-      return {flashData, flashActData, flashSideData};
+      const artworkData = flashData.map(flash => flash.coverArtwork);
+      const commentaryData = flashData.flatMap(flash => flash.commentary);
+      const creditingSourceData = flashData.flatMap(flash => flash.creditingSources);
+
+      return {
+        flashData,
+        flashActData,
+        flashSideData,
+
+        artworkData,
+        commentaryData,
+        creditingSourceData,
+      };
     },
 
     sort({flashData}) {
diff --git a/src/data/things/group.js b/src/data/things/group.js
index 8418cb99..0262a3a5 100644
--- a/src/data/things/group.js
+++ b/src/data/things/group.js
@@ -1,8 +1,11 @@
 export const GROUP_DATA_FILE = 'groups.yaml';
 
+import {inspect} from 'node:util';
+
+import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
+import {is} from '#validators';
 import {parseAnnotatedReferences, parseSerieses} from '#yaml';
 
 import {
@@ -12,15 +15,16 @@ import {
   directory,
   name,
   referenceList,
-  seriesList,
+  soupyFind,
+  thing,
+  thingList,
   urls,
-  wikiData,
 } from '#composite/wiki-properties';
 
 export class Group extends Thing {
   static [Thing.referenceType] = 'group';
 
-  static [Thing.getPropertyDescriptors] = ({Album, Artist}) => ({
+  static [Thing.getPropertyDescriptors] = ({Album, Artist, Series}) => ({
     // Update & expose
 
     name: name('Unnamed Group'),
@@ -32,10 +36,7 @@ export class Group extends Thing {
 
     closelyLinkedArtists: annotatedReferenceList({
       class: input.value(Artist),
-      find: input.value(find.artist),
-      data: 'artistData',
-
-      date: input.value(null),
+      find: soupyFind.input('artist'),
 
       reference: input.value('artist'),
       thing: input.value('artist'),
@@ -43,27 +44,17 @@ export class Group extends Thing {
 
     featuredAlbums: referenceList({
       class: input.value(Album),
-      find: input.value(find.album),
-      data: 'albumData',
+      find: soupyFind.input('album'),
     }),
 
-    serieses: seriesList({
-      group: input.myself(),
+    serieses: thingList({
+      class: input.value(Series),
     }),
 
     // Update only
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
-
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
-
-    groupCategoryData: wikiData({
-      class: input.value(GroupCategory),
-    }),
+    find: soupyFind(),
+    reverse: soupyFind(),
 
     // Expose only
 
@@ -83,9 +74,9 @@ export class Group extends Thing {
       flags: {expose: true},
 
       expose: {
-        dependencies: ['this', 'albumData'],
-        compute: ({this: group, albumData}) =>
-          albumData?.filter((album) => album.groups.includes(group)) ?? [],
+        dependencies: ['this', 'reverse'],
+        compute: ({this: group, reverse}) =>
+          reverse.albumsWhoseGroupsInclude(group),
       },
     },
 
@@ -93,9 +84,9 @@ export class Group extends Thing {
       flags: {expose: true},
 
       expose: {
-        dependencies: ['this', 'groupCategoryData'],
-        compute: ({this: group, groupCategoryData}) =>
-          groupCategoryData.find((category) => category.groups.includes(group))
+        dependencies: ['this', 'reverse'],
+        compute: ({this: group, reverse}) =>
+          reverse.groupCategoriesWhichInclude(group, {unique: true})
             ?.color,
       },
     },
@@ -104,9 +95,9 @@ export class Group extends Thing {
       flags: {expose: true},
 
       expose: {
-        dependencies: ['this', 'groupCategoryData'],
-        compute: ({this: group, groupCategoryData}) =>
-          groupCategoryData.find((category) => category.groups.includes(group)) ??
+        dependencies: ['this', 'reverse'],
+        compute: ({this: group, reverse}) =>
+          reverse.groupCategoriesWhichInclude(group, {unique: true}) ??
           null,
       },
     },
@@ -119,6 +110,25 @@ export class Group extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    groupsCloselyLinkedTo: {
+      bindTo: 'groupData',
+
+      referencing: group =>
+        group.closelyLinkedArtists
+          .map(({artist, ...referenceDetails}) => ({
+            group,
+            artist,
+            referenceDetails,
+          })),
+
+      referenced: ({artist}) => [artist],
+
+      tidy: ({group, referenceDetails}) =>
+        ({group, ...referenceDetails}),
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Group': {property: 'name'},
@@ -186,8 +196,9 @@ export class Group extends Thing {
 
       const groupData = results.filter(x => x instanceof Group);
       const groupCategoryData = results.filter(x => x instanceof GroupCategory);
+      const seriesData = groupData.flatMap(group => group.serieses);
 
-      return {groupData, groupCategoryData};
+      return {groupData, groupCategoryData, seriesData};
     },
 
     // Groups aren't sorted at all, always preserving the order in the data
@@ -210,17 +221,23 @@ export class GroupCategory extends Thing {
 
     groups: referenceList({
       class: input.value(Group),
-      find: input.value(find.group),
-      data: 'groupData',
+      find: soupyFind.input('group'),
     }),
 
     // Update only
 
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
+    find: soupyFind(),
   });
 
+  static [Thing.reverseSpecs] = {
+    groupCategoriesWhichInclude: {
+      bindTo: 'groupCategoryData',
+
+      referencing: groupCategory => [groupCategory],
+      referenced: groupCategory => groupCategory.groups,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Category': {property: 'name'},
@@ -228,3 +245,73 @@ export class GroupCategory extends Thing {
     },
   };
 }
+
+export class Series extends Thing {
+  static [Thing.getPropertyDescriptors] = ({Album, Group}) => ({
+    // Update & expose
+
+    name: name('Unnamed Series'),
+
+    showAlbumArtists: {
+      flags: {update: true, expose: true},
+      update: {
+        validate:
+          is('all', 'differing', 'none'),
+      },
+    },
+
+    description: contentString(),
+
+    group: thing({
+      class: input.value(Group),
+    }),
+
+    albums: referenceList({
+      class: input.value(Album),
+      find: soupyFind.input('album'),
+    }),
+
+    // Update only
+
+    find: soupyFind(),
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Name': {property: 'name'},
+
+      'Description': {property: 'description'},
+
+      'Show Album Artists': {property: 'showAlbumArtists'},
+
+      'Albums': {property: 'albums'},
+    },
+  };
+
+  [inspect.custom](depth, options, inspect) {
+    const parts = [];
+
+    parts.push(Thing.prototype[inspect.custom].apply(this));
+
+    if (depth >= 0) showGroup: {
+      let group = null;
+      try {
+        group = this.group;
+      } catch {
+        break showGroup;
+      }
+
+      const groupName = group.name;
+      const groupIndex = group.serieses.indexOf(this);
+
+      const num =
+        (groupIndex === -1
+          ? 'indeterminate position'
+          : `#${groupIndex + 1}`);
+
+      parts.push(` (${colors.yellow(num)} in ${colors.green(`"${groupName}"`)})`);
+    }
+
+    return parts.join('');
+  }
+}
diff --git a/src/data/things/homepage-layout.js b/src/data/things/homepage-layout.js
index 00d6aef5..3a11c287 100644
--- a/src/data/things/homepage-layout.js
+++ b/src/data/things/homepage-layout.js
@@ -1,8 +1,11 @@
 export const HOMEPAGE_LAYOUT_DATA_FILE = 'homepage.yaml';
 
+import {inspect} from 'node:util';
+
+import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
+import {empty} from '#sugar';
 
 import {
   anyOf,
@@ -11,19 +14,26 @@ import {
   isString,
   isStringNonEmpty,
   validateArrayItems,
-  validateInstanceOf,
   validateReference,
 } from '#validators';
 
 import {exposeDependency} from '#composite/control-flow';
 import {withResolvedReference} from '#composite/wiki-data';
-import {color, contentString, name, referenceList, wikiData}
-  from '#composite/wiki-properties';
+
+import {
+  color,
+  contentString,
+  name,
+  referenceList,
+  soupyFind,
+  thing,
+  thingList,
+} from '#composite/wiki-properties';
 
 export class HomepageLayout extends Thing {
   static [Thing.friendlyName] = `Homepage Layout`;
 
-  static [Thing.getPropertyDescriptors] = ({HomepageLayoutRow}) => ({
+  static [Thing.getPropertyDescriptors] = ({HomepageLayoutSection}) => ({
     // Update & expose
 
     sidebarContent: contentString(),
@@ -31,15 +41,12 @@ export class HomepageLayout extends Thing {
     navbarLinks: {
       flags: {update: true, expose: true},
       update: {validate: validateArrayItems(isStringNonEmpty)},
+      expose: {transform: value => value ?? []},
     },
 
-    rows: {
-      flags: {update: true, expose: true},
-
-      update: {
-        validate: validateArrayItems(validateInstanceOf(HomepageLayoutRow)),
-      },
-    },
+    sections: thingList({
+      class: input.value(HomepageLayoutSection),
+    }),
   });
 
   static [Thing.yamlDocumentSpec] = {
@@ -50,85 +57,230 @@ export class HomepageLayout extends Thing {
       'Navbar Links': {property: 'navbarLinks'},
     },
   };
+
+  static [Thing.getYamlLoadingSpec] = ({
+    documentModes: {allInOne},
+    thingConstructors: {
+      HomepageLayout,
+      HomepageLayoutSection,
+    },
+  }) => ({
+    title: `Process homepage layout file`,
+    file: HOMEPAGE_LAYOUT_DATA_FILE,
+
+    documentMode: allInOne,
+    documentThing: document => {
+      if (document['Homepage']) {
+        return HomepageLayout;
+      }
+
+      if (document['Section']) {
+        return HomepageLayoutSection;
+      }
+
+      if (document['Row']) {
+        switch (document['Row']) {
+          case 'actions':
+            return HomepageLayoutActionsRow;
+          case 'album carousel':
+            return HomepageLayoutAlbumCarouselRow;
+          case 'album grid':
+            return HomepageLayoutAlbumGridRow;
+          default:
+            throw new TypeError(`Unrecognized row type ${document['Row']}`);
+        }
+      }
+
+      return null;
+    },
+
+    save(results) {
+      if (!empty(results) && !(results[0] instanceof HomepageLayout)) {
+        throw new Error(`Expected 'Homepage' document at top of homepage layout file`);
+      }
+
+      const homepageLayout = results[0];
+      const sections = [];
+
+      let currentSection = null;
+      let currentSectionRows = [];
+
+      const closeCurrentSection = () => {
+        if (currentSection) {
+          for (const row of currentSectionRows) {
+            row.section = currentSection;
+          }
+
+          currentSection.rows = currentSectionRows;
+          sections.push(currentSection);
+
+          currentSection = null;
+          currentSectionRows = [];
+        }
+      };
+
+      for (const entry of results.slice(1)) {
+        if (entry instanceof HomepageLayout) {
+          throw new Error(`Expected only one 'Homepage' document in total`);
+        } else if (entry instanceof HomepageLayoutSection) {
+          closeCurrentSection();
+          currentSection = entry;
+        } else if (entry instanceof HomepageLayoutRow) {
+          if (currentSection) {
+            currentSectionRows.push(entry);
+          } else {
+            throw new Error(`Expected a 'Section' document to add following rows into`);
+          }
+        }
+      }
+
+      closeCurrentSection();
+
+      homepageLayout.sections = sections;
+
+      return {homepageLayout};
+    },
+  });
+}
+
+export class HomepageLayoutSection extends Thing {
+  static [Thing.friendlyName] = `Homepage Section`;
+
+  static [Thing.getPropertyDescriptors] = ({HomepageLayoutRow}) => ({
+    // Update & expose
+
+    name: name(`Unnamed Homepage Section`),
+
+    color: color(),
+
+    rows: thingList({
+      class: input.value(HomepageLayoutRow),
+    }),
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Section': {property: 'name'},
+      'Color': {property: 'color'},
+    },
+  };
 }
 
 export class HomepageLayoutRow extends Thing {
   static [Thing.friendlyName] = `Homepage Row`;
 
-  static [Thing.getPropertyDescriptors] = ({Album, Group}) => ({
+  static [Thing.getPropertyDescriptors] = ({HomepageLayoutSection}) => ({
     // Update & expose
 
-    name: name('Unnamed Homepage Row'),
+    section: thing({
+      class: input.value(HomepageLayoutSection),
+    }),
+
+    // Update only
+
+    find: soupyFind(),
+
+    // Expose only
 
     type: {
-      flags: {update: true, expose: true},
+      flags: {expose: true},
 
-      update: {
-        validate() {
+      expose: {
+        compute() {
           throw new Error(`'type' property validator must be overridden`);
         },
       },
     },
+  });
 
-    color: color(),
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Row': {ignore: true},
+    },
+  };
 
-    // Update only
+  [inspect.custom](depth) {
+    const parts = [];
 
-    // These wiki data arrays aren't necessarily used by every subclass, but
-    // to the convenience of providing these, the superclass accepts all wiki
-    // data arrays depended upon by any subclass.
+    parts.push(Thing.prototype[inspect.custom].apply(this));
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
+    if (depth >= 0 && this.section) {
+      const sectionName = this.section.name;
+      const index = this.section.rows.indexOf(this);
+      const rowNum =
+        (index === -1
+          ? 'indeterminate position'
+          : `#${index + 1}`);
+      parts.push(` (${colors.yellow(rowNum)} in ${colors.green(sectionName)})`);
+    }
 
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
+    return parts.join('');
+  }
+}
+
+export class HomepageLayoutActionsRow extends HomepageLayoutRow {
+  static [Thing.friendlyName] = `Homepage Actions Row`;
+
+  static [Thing.getPropertyDescriptors] = (opts) => ({
+    ...HomepageLayoutRow[Thing.getPropertyDescriptors](opts),
+
+    // Update & expose
+
+    actionLinks: {
+      flags: {update: true, expose: true},
+      update: {validate: validateArrayItems(isString)},
+    },
+
+    // Expose only
+
+    type: {
+      flags: {expose: true},
+      expose: {compute: () => 'actions'},
+    },
   });
 
-  static [Thing.yamlDocumentSpec] = {
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(HomepageLayoutRow, {
     fields: {
-      'Row': {property: 'name'},
-      'Color': {property: 'color'},
-      'Type': {property: 'type'},
+      'Actions': {property: 'actionLinks'},
     },
-  };
+  });
 }
 
-export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
-  static [Thing.friendlyName] = `Homepage Albums Row`;
+export class HomepageLayoutAlbumCarouselRow extends HomepageLayoutRow {
+  static [Thing.friendlyName] = `Homepage Album Carousel Row`;
 
-  static [Thing.getPropertyDescriptors] = (opts, {Album, Group} = opts) => ({
+  static [Thing.getPropertyDescriptors] = (opts, {Album} = opts) => ({
     ...HomepageLayoutRow[Thing.getPropertyDescriptors](opts),
 
     // Update & expose
 
+    albums: referenceList({
+      class: input.value(Album),
+      find: soupyFind.input('album'),
+    }),
+
+    // Expose only
+
     type: {
-      flags: {update: true, expose: true},
-      update: {
-        validate(value) {
-          if (value !== 'albums') {
-            throw new TypeError(`Expected 'albums'`);
-          }
+      flags: {expose: true},
+      expose: {compute: () => 'album carousel'},
+    },
+  });
 
-          return true;
-        },
-      },
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(HomepageLayoutRow, {
+    fields: {
+      'Albums': {property: 'albums'},
     },
+  });
+}
 
-    displayStyle: {
-      flags: {update: true, expose: true},
+export class HomepageLayoutAlbumGridRow extends HomepageLayoutRow {
+  static [Thing.friendlyName] = `Homepage Album Grid Row`;
 
-      update: {
-        validate: is('grid', 'carousel'),
-      },
+  static [Thing.getPropertyDescriptors] = (opts, {Album, Group} = opts) => ({
+    ...HomepageLayoutRow[Thing.getPropertyDescriptors](opts),
 
-      expose: {
-        transform: (displayStyle) =>
-          displayStyle ?? 'grid',
-      },
-    },
+    // Update & expose
 
     sourceGroup: [
       {
@@ -151,8 +303,7 @@ export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
 
       withResolvedReference({
         ref: input.updateValue(),
-        data: 'groupData',
-        find: input.value(find.group),
+        find: soupyFind.input('group'),
       }),
 
       exposeDependency({dependency: '#resolvedReference'}),
@@ -160,8 +311,7 @@ export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
 
     sourceAlbums: referenceList({
       class: input.value(Album),
-      find: input.value(find.album),
-      data: 'albumData',
+      find: soupyFind.input('album'),
     }),
 
     countAlbumsFromGroup: {
@@ -169,55 +319,19 @@ export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
       update: {validate: isCountingNumber},
     },
 
-    actionLinks: {
-      flags: {update: true, expose: true},
-      update: {validate: validateArrayItems(isString)},
+    // Expose only
+
+    type: {
+      flags: {expose: true},
+      expose: {compute: () => 'album grid'},
     },
   });
 
   static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(HomepageLayoutRow, {
     fields: {
-      'Display Style': {property: 'displayStyle'},
       'Group': {property: 'sourceGroup'},
       'Count': {property: 'countAlbumsFromGroup'},
       'Albums': {property: 'sourceAlbums'},
-      'Actions': {property: 'actionLinks'},
-    },
-  });
-
-  static [Thing.getYamlLoadingSpec] = ({
-    documentModes: {headerAndEntries}, // Kludge, see below
-    thingConstructors: {
-      HomepageLayout,
-      HomepageLayoutAlbumsRow,
-    },
-  }) => ({
-    title: `Process homepage layout file`,
-
-    // Kludge: This benefits from the same headerAndEntries style messaging as
-    // albums and tracks (for example), but that document mode is designed to
-    // support multiple files, and only one is actually getting processed here.
-    files: [HOMEPAGE_LAYOUT_DATA_FILE],
-
-    documentMode: headerAndEntries,
-    headerDocumentThing: HomepageLayout,
-    entryDocumentThing: document => {
-      switch (document['Type']) {
-        case 'albums':
-          return HomepageLayoutAlbumsRow;
-        default:
-          throw new TypeError(`No processDocument function for row type ${document['Type']}!`);
-      }
-    },
-
-    save(results) {
-      if (!results[0]) {
-        return;
-      }
-
-      const {header: homepageLayout, entries: rows} = results[0];
-      Object.assign(homepageLayout, {rows});
-      return {homepageLayout};
     },
   });
 }
diff --git a/src/data/things/index.js b/src/data/things/index.js
index f18e283a..11307b50 100644
--- a/src/data/things/index.js
+++ b/src/data/things/index.js
@@ -6,31 +6,42 @@ import CacheableObject from '#cacheable-object';
 import {logError} from '#cli';
 import {compositeFrom} from '#composite';
 import * as serialize from '#serialize';
+import {withEntries} from '#sugar';
 import Thing from '#thing';
 
+import * as additionalFileClasses from './additional-file.js';
+import * as additionalNameClasses from './additional-name.js';
 import * as albumClasses from './album.js';
 import * as artTagClasses from './art-tag.js';
 import * as artistClasses from './artist.js';
+import * as artworkClasses from './artwork.js';
+import * as contentClasses from './content.js';
 import * as contributionClasses from './contribution.js';
 import * as flashClasses from './flash.js';
 import * as groupClasses from './group.js';
 import * as homepageLayoutClasses from './homepage-layout.js';
 import * as languageClasses from './language.js';
 import * as newsEntryClasses from './news-entry.js';
+import * as sortingRuleClasses from './sorting-rule.js';
 import * as staticPageClasses from './static-page.js';
 import * as trackClasses from './track.js';
 import * as wikiInfoClasses from './wiki-info.js';
 
 const allClassLists = {
+  'additional-file.js': additionalFileClasses,
+  'additional-name.js': additionalNameClasses,
   'album.js': albumClasses,
   'art-tag.js': artTagClasses,
   'artist.js': artistClasses,
+  'artwork.js': artworkClasses,
+  'content.js': contentClasses,
   'contribution.js': contributionClasses,
   'flash.js': flashClasses,
   'group.js': groupClasses,
   'homepage-layout.js': homepageLayoutClasses,
   'language.js': languageClasses,
   'news-entry.js': newsEntryClasses,
+  'sorting-rule.js': sortingRuleClasses,
   'static-page.js': staticPageClasses,
   'track.js': trackClasses,
   'wiki-info.js': wikiInfoClasses,
@@ -79,13 +90,25 @@ function errorDuplicateClassNames() {
 }
 
 function flattenClassLists() {
+  let allClassesUnsorted = Object.create(null);
+
   for (const classes of Object.values(allClassLists)) {
     for (const [name, constructor] of Object.entries(classes)) {
       if (typeof constructor !== 'function') continue;
       if (!(constructor.prototype instanceof Thing)) continue;
-      allClasses[name] = constructor;
+      allClassesUnsorted[name] = constructor;
     }
   }
+
+  // Sort subclasses after their superclasses.
+  Object.assign(allClasses,
+    withEntries(allClassesUnsorted, entries =>
+      entries.sort(({[1]: A}, {[1]: B}) =>
+        (A.prototype instanceof B
+          ? +1
+       : B.prototype instanceof A
+          ? -1
+          :  0))));
 }
 
 function descriptorAggregateHelper({
@@ -177,6 +200,20 @@ function evaluateSerializeDescriptors() {
   });
 }
 
+function finalizeCacheableObjectPrototypes() {
+  return descriptorAggregateHelper({
+    message: `Errors finalizing Thing class prototypes`,
+
+    op(constructor) {
+      constructor.finalizeCacheableObjectPrototype();
+    },
+
+    showFailedClasses(failedClasses) {
+      logError`Failed to finalize cacheable object prototypes for classes: ${failedClasses.join(', ')}`;
+    },
+  });
+}
+
 if (!errorDuplicateClassNames())
   process.exit(1);
 
@@ -188,6 +225,9 @@ if (!evaluatePropertyDescriptors())
 if (!evaluateSerializeDescriptors())
   process.exit(1);
 
+if (!finalizeCacheableObjectPrototypes())
+  process.exit(1);
+
 Object.assign(allClasses, {Thing});
 
 export default allClasses;
diff --git a/src/data/things/language.js b/src/data/things/language.js
index e9aa58be..e3689643 100644
--- a/src/data/things/language.js
+++ b/src/data/things/language.js
@@ -115,7 +115,7 @@ export class Language extends Thing {
     },
 
     // List of descriptors for providing to external link utilities when using
-    // language.formatExternalLink - refer to util/external-links.js for info.
+    // language.formatExternalLink - refer to #external-links for info.
     externalLinkSpec: {
       flags: {update: true, expose: true},
       update: {validate: isExternalLinkSpec},
@@ -135,6 +135,7 @@ export class Language extends Thing {
     },
 
     intl_date: this.#intlHelper(Intl.DateTimeFormat, {full: true}),
+    intl_dateYear: this.#intlHelper(Intl.DateTimeFormat, {year: 'numeric'}),
     intl_number: this.#intlHelper(Intl.NumberFormat),
     intl_listConjunction: this.#intlHelper(Intl.ListFormat, {type: 'conjunction'}),
     intl_listDisjunction: this.#intlHelper(Intl.ListFormat, {type: 'disjunction'}),
@@ -488,22 +489,44 @@ export class Language extends Thing {
     // or both are undefined, that's just blank content.
     const hasStart = startDate !== null && startDate !== undefined;
     const hasEnd = endDate !== null && endDate !== undefined;
-    if (!hasStart || !hasEnd) {
-      if (startDate === endDate) {
-        return html.blank();
-      } else if (hasStart) {
-        throw new Error(`Expected both start and end of date range, got only start`);
-      } else if (hasEnd) {
-        throw new Error(`Expected both start and end of date range, got only end`);
-      } else {
-        throw new Error(`Got mismatched ${startDate}/${endDate} for start and end`);
-      }
+    if (!hasStart && !hasEnd) {
+      return html.blank();
+    } else if (hasStart && !hasEnd) {
+      throw new Error(`Expected both start and end of date range, got only start`);
+    } else if (!hasStart && hasEnd) {
+      throw new Error(`Expected both start and end of date range, got only end`);
     }
 
     this.assertIntlAvailable('intl_date');
     return this.intl_date.formatRange(startDate, endDate);
   }
 
+  formatYear(date) {
+    if (date === null || date === undefined) {
+      return html.blank();
+    }
+
+    this.assertIntlAvailable('intl_dateYear');
+    return this.intl_dateYear.format(date);
+  }
+
+  formatYearRange(startDate, endDate) {
+    // formatYearRange expects both values to be present, but if both are null
+    // or both are undefined, that's just blank content.
+    const hasStart = startDate !== null && startDate !== undefined;
+    const hasEnd = endDate !== null && endDate !== undefined;
+    if (!hasStart && !hasEnd) {
+      return html.blank();
+    } else if (hasStart && !hasEnd) {
+      throw new Error(`Expected both start and end of date range, got only start`);
+    } else if (!hasStart && hasEnd) {
+      throw new Error(`Expected both start and end of date range, got only end`);
+    }
+
+    this.assertIntlAvailable('intl_dateYear');
+    return this.intl_dateYear.formatRange(startDate, endDate);
+  }
+
   formatDateDuration({
     years: numYears = 0,
     months: numMonths = 0,
@@ -842,6 +865,18 @@ export class Language extends Thing {
     }
   }
 
+  typicallyLowerCase(string) {
+    // Utter nonsense implementation, so this only works on strings,
+    // not actual HTML content, and may rudely disrespect *intentful*
+    // capitalization of whatever goes into it.
+
+    if (typeof string !== 'string') return string;
+    if (string.length <= 1) return string;
+    if (/^\S+?[A-Z]/.test(string)) return string;
+
+    return string[0].toLowerCase() + string.slice(1);
+  }
+
   // Utility function to quickly provide a useful string key
   // (generally a prefix) to stuff nested beneath it.
   encapsulate(...args) {
@@ -896,6 +931,7 @@ const countHelper = (stringKey, optionName = stringKey) =>
 Object.assign(Language.prototype, {
   countAdditionalFiles: countHelper('additionalFiles', 'files'),
   countAlbums: countHelper('albums'),
+  countArtTags: countHelper('artTags', 'tags'),
   countArtworks: countHelper('artworks'),
   countCommentaryEntries: countHelper('commentaryEntries', 'entries'),
   countContributions: countHelper('contributions'),
@@ -903,6 +939,7 @@ Object.assign(Language.prototype, {
   countDays: countHelper('days'),
   countFlashes: countHelper('flashes'),
   countMonths: countHelper('months'),
+  countTimesFeatured: countHelper('timesFeatured'),
   countTimesReferenced: countHelper('timesReferenced'),
   countTimesUsed: countHelper('timesUsed'),
   countTracks: countHelper('tracks'),
diff --git a/src/data/things/sorting-rule.js b/src/data/things/sorting-rule.js
new file mode 100644
index 00000000..ccc4ad89
--- /dev/null
+++ b/src/data/things/sorting-rule.js
@@ -0,0 +1,385 @@
+export const SORTING_RULE_DATA_FILE = 'sorting-rules.yaml';
+
+import {readFile, writeFile} from 'node:fs/promises';
+import * as path from 'node:path';
+
+import {chunkByProperties, compareArrays, unique} from '#sugar';
+import Thing from '#thing';
+import {isObject, isStringNonEmpty, anyOf, strictArrayOf} from '#validators';
+
+import {
+  compareCaseLessSensitive,
+  sortByDate,
+  sortByDirectory,
+  sortByName,
+} from '#sort';
+
+import {
+  documentModes,
+  flattenThingLayoutToDocumentOrder,
+  getThingLayoutForFilename,
+  reorderDocumentsInYAMLSourceText,
+} from '#yaml';
+
+import {flag} from '#composite/wiki-properties';
+
+function isSelectFollowingEntry(value) {
+  isObject(value);
+
+  const {length} = Object.keys(value);
+  if (length !== 1) {
+    throw new Error(`Expected object with 1 key, got ${length}`);
+  }
+
+  return true;
+}
+
+export class SortingRule extends Thing {
+  static [Thing.friendlyName] = `Sorting Rule`;
+
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    active: flag(true),
+
+    message: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Message': {property: 'message'},
+      'Active': {property: 'active'},
+    },
+  };
+
+  static [Thing.getYamlLoadingSpec] = ({
+    documentModes: {allInOne},
+    thingConstructors: {DocumentSortingRule},
+  }) => ({
+    title: `Process sorting rules file`,
+    file: SORTING_RULE_DATA_FILE,
+
+    documentMode: allInOne,
+    documentThing: document =>
+      (document['Sort Documents']
+        ? DocumentSortingRule
+        : null),
+
+    save: (results) => ({sortingRules: results}),
+  });
+
+  check(opts) {
+    return this.constructor.check(this, opts);
+  }
+
+  apply(opts) {
+    return this.constructor.apply(this, opts);
+  }
+
+  static check(rule, opts) {
+    const result = this.apply(rule, {...opts, dry: true});
+    if (!result) return true;
+    if (!result.changed) return true;
+    return false;
+  }
+
+  static async apply(_rule, _opts) {
+    throw new Error(`Not implemented`);
+  }
+
+  static async* applyAll(_rules, _opts) {
+    throw new Error(`Not implemented`);
+  }
+
+  static async* go({dataPath, wikiData, dry}) {
+    const rules = wikiData.sortingRules;
+    const constructors = unique(rules.map(rule => rule.constructor));
+
+    for (const constructor of constructors) {
+      yield* constructor.applyAll(
+        rules
+          .filter(rule => rule.active)
+          .filter(rule => rule.constructor === constructor),
+        {dataPath, wikiData, dry});
+    }
+  }
+}
+
+export class ThingSortingRule extends SortingRule {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    properties: {
+      flags: {update: true, expose: true},
+      update: {
+        validate: strictArrayOf(isStringNonEmpty),
+      },
+    },
+  });
+
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(SortingRule, {
+    fields: {
+      'By Properties': {property: 'properties'},
+    },
+  });
+
+  sort(sortable) {
+    if (this.properties) {
+      for (const property of this.properties.slice().reverse()) {
+        const get = thing => thing[property];
+        const lc = property.toLowerCase();
+
+        if (lc.endsWith('date')) {
+          sortByDate(sortable, {getDate: get});
+          continue;
+        }
+
+        if (lc.endsWith('directory')) {
+          sortByDirectory(sortable, {getDirectory: get});
+          continue;
+        }
+
+        if (lc.endsWith('name')) {
+          sortByName(sortable, {getName: get});
+          continue;
+        }
+
+        const values = sortable.map(get);
+
+        if (values.every(v => typeof v === 'string')) {
+          sortable.sort((a, b) =>
+            compareCaseLessSensitive(get(a), get(b)));
+          continue;
+        }
+
+        if (values.every(v => typeof v === 'number')) {
+          sortable.sort((a, b) => get(a) - get(b));
+          continue;
+        }
+
+        sortable.sort((a, b) =>
+          (get(a).toString() < get(b).toString()
+            ? -1
+         : get(a).toString() > get(b).toString()
+            ? +1
+            :  0));
+      }
+    }
+
+    return sortable;
+  }
+}
+
+export class DocumentSortingRule extends ThingSortingRule {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    // TODO: glob :plead:
+    filename: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+
+    message: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+
+      expose: {
+        dependencies: ['filename'],
+        transform: (value, {filename}) =>
+          value ??
+          `Sort ${filename}`,
+      },
+    },
+
+    selectDocumentsFollowing: {
+      flags: {update: true, expose: true},
+
+      update: {
+        validate:
+          anyOf(
+            isSelectFollowingEntry,
+            strictArrayOf(isSelectFollowingEntry)),
+      },
+
+      compute: {
+        transform: value =>
+          (Array.isArray(value)
+            ? value
+            : [value]),
+      },
+    },
+
+    selectDocumentsUnder: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+  });
+
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(ThingSortingRule, {
+    fields: {
+      'Sort Documents': {property: 'filename'},
+      'Select Documents Following': {property: 'selectDocumentsFollowing'},
+      'Select Documents Under': {property: 'selectDocumentsUnder'},
+    },
+
+    invalidFieldCombinations: [
+      {message: `Specify only one of these`, fields: [
+        'Select Documents Following',
+        'Select Documents Under',
+      ]},
+    ],
+  });
+
+  static async apply(rule, {wikiData, dataPath, dry}) {
+    const oldLayout = getThingLayoutForFilename(rule.filename, wikiData);
+    if (!oldLayout) return null;
+
+    const newLayout = rule.#processLayout(oldLayout);
+
+    const oldOrder = flattenThingLayoutToDocumentOrder(oldLayout);
+    const newOrder = flattenThingLayoutToDocumentOrder(newLayout);
+    const changed = compareArrays(oldOrder, newOrder);
+
+    if (dry) return {changed};
+
+    const realPath =
+      path.join(
+        dataPath,
+        rule.filename.split(path.posix.sep).join(path.sep));
+
+    const oldSourceText = await readFile(realPath, 'utf8');
+    const newSourceText = reorderDocumentsInYAMLSourceText(oldSourceText, newOrder);
+
+    await writeFile(realPath, newSourceText);
+
+    return {changed};
+  }
+
+  static async* applyAll(rules, {wikiData, dataPath, dry}) {
+    rules =
+      rules
+        .slice()
+        .sort((a, b) => a.filename.localeCompare(b.filename, 'en'));
+
+    for (const {chunk, filename} of chunkByProperties(rules, ['filename'])) {
+      const initialLayout = getThingLayoutForFilename(filename, wikiData);
+      if (!initialLayout) continue;
+
+      let currLayout = initialLayout;
+      let prevLayout = initialLayout;
+      let anyChanged = false;
+
+      for (const rule of chunk) {
+        currLayout = rule.#processLayout(currLayout);
+
+        const prevOrder = flattenThingLayoutToDocumentOrder(prevLayout);
+        const currOrder = flattenThingLayoutToDocumentOrder(currLayout);
+
+        if (compareArrays(currOrder, prevOrder)) {
+          yield {rule, changed: false};
+        } else {
+          anyChanged = true;
+          yield {rule, changed: true};
+        }
+
+        prevLayout = currLayout;
+      }
+
+      if (!anyChanged) continue;
+      if (dry) continue;
+
+      const newLayout = currLayout;
+      const newOrder = flattenThingLayoutToDocumentOrder(newLayout);
+
+      const realPath =
+        path.join(
+          dataPath,
+          filename.split(path.posix.sep).join(path.sep));
+
+      const oldSourceText = await readFile(realPath, 'utf8');
+      const newSourceText = reorderDocumentsInYAMLSourceText(oldSourceText, newOrder);
+
+      await writeFile(realPath, newSourceText);
+    }
+  }
+
+  #processLayout(layout) {
+    const fresh = {...layout};
+
+    let sortable = null;
+    switch (fresh.documentMode) {
+      case documentModes.headerAndEntries:
+        sortable = fresh.entryThings =
+          fresh.entryThings.slice();
+        break;
+
+      case documentModes.allInOne:
+        sortable = fresh.things =
+          fresh.things.slice();
+        break;
+
+      default:
+        throw new Error(`Invalid document type for sorting`);
+    }
+
+    if (this.selectDocumentsFollowing) {
+      for (const entry of this.selectDocumentsFollowing) {
+        const [field, value] = Object.entries(entry)[0];
+
+        const after =
+          sortable.findIndex(thing =>
+            thing[Thing.yamlSourceDocument][field] === value);
+
+        const different =
+          after +
+          sortable
+            .slice(after)
+            .findIndex(thing =>
+              Object.hasOwn(thing[Thing.yamlSourceDocument], field) &&
+              thing[Thing.yamlSourceDocument][field] !== value);
+
+        const before =
+          (different === -1
+            ? sortable.length
+            : different);
+
+        const subsortable =
+          sortable.slice(after + 1, before);
+
+        this.sort(subsortable);
+
+        sortable.splice(after + 1, before - after - 1, ...subsortable);
+      }
+    } else if (this.selectDocumentsUnder) {
+      const field = this.selectDocumentsUnder;
+
+      const indices =
+        Array.from(sortable.entries())
+          .filter(([_index, thing]) =>
+            Object.hasOwn(thing[Thing.yamlSourceDocument], field))
+          .map(([index, _thing]) => index);
+
+      for (const [indicesIndex, after] of indices.entries()) {
+        const before =
+          (indicesIndex === indices.length - 1
+            ? sortable.length
+            : indices[indicesIndex + 1]);
+
+        const subsortable =
+          sortable.slice(after + 1, before);
+
+        this.sort(subsortable);
+
+        sortable.splice(after + 1, before - after - 1, ...subsortable);
+      }
+    } else {
+      this.sort(sortable);
+    }
+
+    return fresh;
+  }
+}
diff --git a/src/data/things/static-page.js b/src/data/things/static-page.js
index 03274979..52a09c31 100644
--- a/src/data/things/static-page.js
+++ b/src/data/things/static-page.js
@@ -7,7 +7,7 @@ import {sortAlphabetically} from '#sort';
 import Thing from '#thing';
 import {isName} from '#validators';
 
-import {contentString, directory, name, simpleString}
+import {contentString, directory, flag, name, simpleString}
   from '#composite/wiki-properties';
 
 export class StaticPage extends Thing {
@@ -30,9 +30,12 @@ export class StaticPage extends Thing {
     },
 
     directory: directory(),
-    content: contentString(),
+
     stylesheet: simpleString(),
     script: simpleString(),
+    content: contentString(),
+
+    absoluteLinks: flag(),
   });
 
   static [Thing.findSpecs] = {
@@ -48,6 +51,8 @@ export class StaticPage extends Thing {
       'Short Name': {property: 'nameShort'},
       'Directory': {property: 'directory'},
 
+      'Absolute Links': {property: 'absoluteLinks'},
+
       'Style': {property: 'stylesheet'},
       'Script': {property: 'script'},
       'Content': {property: 'content'},
diff --git a/src/data/things/track.js b/src/data/things/track.js
index a0d2f641..8b9420c7 100644
--- a/src/data/things/track.js
+++ b/src/data/things/track.js
@@ -3,7 +3,6 @@ import {inspect} from 'node:util';
 import CacheableObject from '#cacheable-object';
 import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
 import {isBoolean, isColor, isContributionList, isDate, isFileExtension}
   from '#validators';
@@ -12,16 +11,20 @@ import {
   parseAdditionalFiles,
   parseAdditionalNames,
   parseAnnotatedReferences,
+  parseArtwork,
+  parseCommentary,
   parseContributors,
+  parseCreditingSources,
+  parseReferencingSources,
   parseDate,
   parseDimensions,
   parseDuration,
+  parseLyrics,
 } from '#yaml';
 
 import {withPropertyFromObject} from '#composite/data';
 
 import {
-  exitWithoutDependency,
   exposeConstant,
   exposeDependency,
   exposeDependencyOrContinue,
@@ -36,11 +39,8 @@ import {
 } from '#composite/wiki-data';
 
 import {
-  additionalFiles,
-  additionalNameList,
-  commentary,
   commentatorArtists,
-  contentString,
+  constitutibleArtworkList,
   contributionList,
   dimensions,
   directory,
@@ -50,42 +50,49 @@ import {
   referenceList,
   referencedArtworkList,
   reverseReferenceList,
-  reverseReferencedArtworkList,
   simpleDate,
   simpleString,
   singleReference,
+  soupyFind,
+  soupyReverse,
   thing,
+  thingList,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
 
 import {
   exitWithoutUniqueCoverArt,
-  inheritContributionListFromOriginalRelease,
-  inheritFromOriginalRelease,
-  trackReverseReferenceList,
-  withAlbum,
+  inheritContributionListFromMainRelease,
+  inheritFromMainRelease,
+  withAllReleases,
   withAlwaysReferenceByDirectory,
   withContainingTrackSection,
+  withCoverArtistContribs,
   withDate,
   withDirectorySuffix,
   withHasUniqueCoverArt,
-  withOriginalRelease,
+  withMainRelease,
   withOtherReleases,
   withPropertyFromAlbum,
   withSuffixDirectoryFromAlbum,
   withTrackArtDate,
+  withTrackNumber,
 } from '#composite/things/track';
 
 export class Track extends Thing {
   static [Thing.referenceType] = 'track';
 
   static [Thing.getPropertyDescriptors] = ({
+    AdditionalFile,
+    AdditionalName,
     Album,
     ArtTag,
-    Artist,
-    Flash,
-    TrackSection,
+    Artwork,
+    CommentaryEntry,
+    CreditingSourcesEntry,
+    LyricsEntry,
+    ReferencingSourcesEntry,
     WikiInfo,
   }) => ({
     // Update & expose
@@ -122,7 +129,13 @@ export class Track extends Thing {
       })
     ],
 
-    additionalNames: additionalNameList(),
+    album: thing({
+      class: input.value(Album),
+    }),
+
+    additionalNames: thingList({
+      class: input.value(AdditionalName),
+    }),
 
     bandcampTrackIdentifier: simpleString(),
     bandcampArtworkIdentifier: simpleString(),
@@ -157,6 +170,18 @@ export class Track extends Thing {
       exposeDependency({dependency: '#alwaysReferenceByDirectory'}),
     ],
 
+    countInArtistTotals: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(isBoolean),
+      }),
+
+      withPropertyFromAlbum({
+        property: input.value('countTracksInArtistTotals'),
+      }),
+
+      exposeDependency({dependency: '#album.countTracksInArtistTotals'}),
+    ],
+
     // Disables presenting the track as though it has its own unique artwork.
     // This flag should only be used in select circumstances, i.e. to override
     // an album's trackCoverArtists. This flag supercedes that property, as well
@@ -198,6 +223,8 @@ export class Track extends Thing {
     coverArtDimensions: [
       exitWithoutUniqueCoverArt(),
 
+      exposeUpdateValueOrContinue(),
+
       withPropertyFromAlbum({
         property: input.value('trackDimensions'),
       }),
@@ -207,35 +234,48 @@ export class Track extends Thing {
       dimensions(),
     ],
 
-    commentary: commentary(),
-    creditSources: commentary(),
+    commentary: thingList({
+      class: input.value(CommentaryEntry),
+    }),
+
+    creditingSources: thingList({
+      class: input.value(CreditingSourcesEntry),
+    }),
+
+    referencingSources: thingList({
+      class: input.value(ReferencingSourcesEntry),
+    }),
 
     lyrics: [
-      inheritFromOriginalRelease(),
-      contentString(),
+      // TODO: Inherited lyrics are literally the same objects, so of course
+      // their .thing properties aren't going to point back to this one, and
+      // certainly couldn't be recontextualized...
+      inheritFromMainRelease(),
+
+      thingList({
+        class: input.value(LyricsEntry),
+      }),
     ],
 
-    additionalFiles: additionalFiles(),
-    sheetMusicFiles: additionalFiles(),
-    midiProjectFiles: additionalFiles(),
+    additionalFiles: thingList({
+      class: input.value(AdditionalFile),
+    }),
 
-    originalReleaseTrack: singleReference({
-      class: input.value(Track),
-      find: input.value(find.track),
-      data: 'trackData',
+    sheetMusicFiles: thingList({
+      class: input.value(AdditionalFile),
     }),
 
-    // Internal use only - for directly identifying an album inside a track's
-    // util.inspect display, if it isn't indirectly available (by way of being
-    // included in an album's track list).
-    dataSourceAlbum: singleReference({
-      class: input.value(Album),
-      find: input.value(find.album),
-      data: 'albumData',
+    midiProjectFiles: thingList({
+      class: input.value(AdditionalFile),
+    }),
+
+    mainReleaseTrack: singleReference({
+      class: input.value(Track),
+      find: soupyFind.input('track'),
     }),
 
     artistContribs: [
-      inheritContributionListFromOriginalRelease(),
+      inheritContributionListFromMainRelease(),
 
       withDate(),
 
@@ -271,7 +311,7 @@ export class Track extends Thing {
     ],
 
     contributorContribs: [
-      inheritContributionListFromOriginalRelease(),
+      inheritContributionListFromMainRelease(),
 
       withDate(),
 
@@ -281,71 +321,45 @@ export class Track extends Thing {
       }),
     ],
 
-    // Cover artists aren't inherited from the original release, since it
-    // typically varies by release and isn't defined by the musical qualities
-    // of the track.
     coverArtistContribs: [
-      exitWithoutUniqueCoverArt({
-        value: input.value([]),
-      }),
-
-      withTrackArtDate({
-        fallback: input.value(true),
-      }),
-
-      withResolvedContribs({
-        from: input.updateValue({validate: isContributionList}),
-        thingProperty: input.thisProperty(),
-        artistProperty: input.value('trackCoverArtistContributions'),
-        date: '#trackArtDate',
-      }).outputs({
-        '#resolvedContribs': '#coverArtistContribs',
-      }),
-
-      exposeDependencyOrContinue({
-        dependency: '#coverArtistContribs',
-        mode: input.value('empty'),
-      }),
-
-      withPropertyFromAlbum({
-        property: input.value('trackCoverArtistContribs'),
-      }),
-
-      withRecontextualizedContributionList({
-        list: '#album.trackCoverArtistContribs',
-        artistProperty: input.value('trackCoverArtistContributions'),
-      }),
-
-      withRedatedContributionList({
-        list: '#album.trackCoverArtistContribs',
-        date: '#trackArtDate',
+      withCoverArtistContribs({
+        from: input.updateValue({
+          validate: isContributionList,
+        }),
       }),
 
-      exposeDependency({dependency: '#album.trackCoverArtistContribs'}),
+      exposeDependency({dependency: '#coverArtistContribs'}),
     ],
 
     referencedTracks: [
-      inheritFromOriginalRelease({
+      inheritFromMainRelease({
         notFoundValue: input.value([]),
       }),
 
       referenceList({
         class: input.value(Track),
-        find: input.value(find.track),
-        data: 'trackData',
+        find: soupyFind.input('track'),
       }),
     ],
 
     sampledTracks: [
-      inheritFromOriginalRelease({
+      inheritFromMainRelease({
         notFoundValue: input.value([]),
       }),
 
       referenceList({
         class: input.value(Track),
-        find: input.value(find.track),
-        data: 'trackData',
+        find: soupyFind.input('track'),
+      }),
+    ],
+
+    trackArtworks: [
+      exitWithoutUniqueCoverArt({
+        value: input.value([]),
       }),
+
+      constitutibleArtworkList.fromYAMLFieldSpec
+        .call(this, 'Track Artwork'),
     ],
 
     artTags: [
@@ -355,8 +369,7 @@ export class Track extends Thing {
 
       referenceList({
         class: input.value(ArtTag),
-        find: input.value(find.artTag),
-        data: 'artTagData',
+        find: soupyFind.input('artTag'),
       }),
     ],
 
@@ -365,41 +378,25 @@ export class Track extends Thing {
         value: input.value([]),
       }),
 
-      withTrackArtDate({
-        fallback: input.value(true),
-      }),
-
-      referencedArtworkList({
-        date: '#trackArtDate',
-      }),
+      referencedArtworkList(),
     ],
 
     // Update only
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
-
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
-
-    artTagData: wikiData({
-      class: input.value(ArtTag),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
-    flashData: wikiData({
-      class: input.value(Flash),
+    // used for referencedArtworkList (mixedFind)
+    artworkData: wikiData({
+      class: input.value(Artwork),
     }),
 
+    // used for withAlwaysReferenceByDirectory (for some reason)
     trackData: wikiData({
       class: input.value(Track),
     }),
 
-    trackSectionData: wikiData({
-      class: input.value(TrackSection),
-    }),
-
+    // used for withMatchingContributionPresets (indirectly by Contribution)
     wikiInfo: thing({
       class: input.value(WikiInfo),
     }),
@@ -408,63 +405,75 @@ export class Track extends Thing {
 
     commentatorArtists: commentatorArtists(),
 
-    album: [
-      withAlbum(),
-      exposeDependency({dependency: '#album'}),
-    ],
-
     date: [
       withDate(),
       exposeDependency({dependency: '#date'}),
     ],
 
+    trackNumber: [
+      withTrackNumber(),
+      exposeDependency({dependency: '#trackNumber'}),
+    ],
+
     hasUniqueCoverArt: [
       withHasUniqueCoverArt(),
       exposeDependency({dependency: '#hasUniqueCoverArt'}),
     ],
 
-    isOriginalRelease: [
-      withOriginalRelease(),
+    isMainRelease: [
+      withMainRelease(),
 
       exposeWhetherDependencyAvailable({
-        dependency: '#originalRelease',
+        dependency: '#mainRelease',
         negate: input.value(true),
       }),
     ],
 
-    isRerelease: [
-      withOriginalRelease(),
+    isSecondaryRelease: [
+      withMainRelease(),
 
       exposeWhetherDependencyAvailable({
-        dependency: '#originalRelease',
+        dependency: '#mainRelease',
       }),
     ],
 
+    // Only has any value for main releases, because secondary releases
+    // are never secondary to *another* secondary release.
+    secondaryReleases: reverseReferenceList({
+      reverse: soupyReverse.input('tracksWhichAreSecondaryReleasesOf'),
+    }),
+
+    allReleases: [
+      withAllReleases(),
+      exposeDependency({dependency: '#allReleases'}),
+    ],
+
     otherReleases: [
       withOtherReleases(),
       exposeDependency({dependency: '#otherReleases'}),
     ],
 
-    referencedByTracks: trackReverseReferenceList({
-      list: input.value('referencedTracks'),
+    groups: [
+      withPropertyFromAlbum({
+        property: input.value('groups'),
+      }),
+
+      exposeDependency({
+        dependency: '#album.groups',
+      }),
+    ],
+
+    referencedByTracks: reverseReferenceList({
+      reverse: soupyReverse.input('tracksWhichReference'),
     }),
 
-    sampledByTracks: trackReverseReferenceList({
-      list: input.value('sampledTracks'),
+    sampledByTracks: reverseReferenceList({
+      reverse: soupyReverse.input('tracksWhichSample'),
     }),
 
     featuredInFlashes: reverseReferenceList({
-      data: 'flashData',
-      list: input.value('featuredTracks'),
+      reverse: soupyReverse.input('flashesWhichFeature'),
     }),
-
-    referencedByArtworks: [
-      exitWithoutUniqueCoverArt({
-        value: input.value([]),
-      }),
-
-      reverseReferencedArtworkList(),
-    ],
   });
 
   static [Thing.yamlDocumentSpec] = {
@@ -488,6 +497,8 @@ export class Track extends Thing {
         transform: String,
       },
 
+      'Count In Artist Totals': {property: 'countInArtistTotals'},
+
       'Duration': {
         property: 'duration',
         transform: parseDuration,
@@ -523,9 +534,25 @@ export class Track extends Thing {
 
       'Always Reference By Directory': {property: 'alwaysReferenceByDirectory'},
 
-      'Lyrics': {property: 'lyrics'},
-      'Commentary': {property: 'commentary'},
-      'Credit Sources': {property: 'creditSources'},
+      'Lyrics': {
+        property: 'lyrics',
+        transform: parseLyrics,
+      },
+
+      'Commentary': {
+        property: 'commentary',
+        transform: parseCommentary,
+      },
+
+      'Crediting Sources': {
+        property: 'creditingSources',
+        transform: parseCreditingSources,
+      },
+
+      'Referencing Sources': {
+        property: 'referencingSources',
+        transform: parseReferencingSources,
+      },
 
       'Additional Files': {
         property: 'additionalFiles',
@@ -542,7 +569,7 @@ export class Track extends Thing {
         transform: parseAdditionalFiles,
       },
 
-      'Originally Released As': {property: 'originalReleaseTrack'},
+      'Main Release': {property: 'mainReleaseTrack'},
       'Referenced Tracks': {property: 'referencedTracks'},
       'Sampled Tracks': {property: 'sampledTracks'},
 
@@ -569,34 +596,54 @@ export class Track extends Thing {
         transform: parseContributors,
       },
 
+      'Track Artwork': {
+        property: 'trackArtworks',
+        transform:
+          parseArtwork({
+            thingProperty: 'trackArtworks',
+            dimensionsFromThingProperty: 'coverArtDimensions',
+            fileExtensionFromThingProperty: 'coverArtFileExtension',
+            dateFromThingProperty: 'coverArtDate',
+            artTagsFromThingProperty: 'artTags',
+            referencedArtworksFromThingProperty: 'referencedArtworks',
+            artistContribsFromThingProperty: 'coverArtistContribs',
+            artistContribsArtistProperty: 'trackCoverArtistContributions',
+          }),
+      },
+
       'Art Tags': {property: 'artTags'},
 
       'Review Points': {ignore: true},
     },
 
     invalidFieldCombinations: [
-      {message: `Rereleases inherit references from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases never count in artist totals`, fields: [
+        'Main Release',
+        'Count In Artist Totals',
+      ]},
+
+      {message: `Secondary releases inherit references from the main one`, fields: [
+        'Main Release',
         'Referenced Tracks',
       ]},
 
-      {message: `Rereleases inherit samples from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit samples from the main one`, fields: [
+        'Main Release',
         'Sampled Tracks',
       ]},
 
-      {message: `Rereleases inherit artists from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit artists from the main one`, fields: [
+        'Main Release',
         'Artists',
       ]},
 
-      {message: `Rereleases inherit contributors from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit contributors from the main one`, fields: [
+        'Main Release',
         'Contributors',
       ]},
 
-      {message: `Rereleases inherit lyrics from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit lyrics from the main one`, fields: [
+        'Main Release',
         'Lyrics',
       ]},
 
@@ -617,6 +664,7 @@ export class Track extends Thing {
   static [Thing.findSpecs] = {
     track: {
       referenceTypes: ['track'],
+
       bindTo: 'trackData',
 
       getMatchableNames: track =>
@@ -625,12 +673,12 @@ export class Track extends Thing {
           : [track.name]),
     },
 
-    trackOriginalReleasesOnly: {
+    trackMainReleasesOnly: {
       referenceTypes: ['track'],
       bindTo: 'trackData',
 
       include: track =>
-        !CacheableObject.getUpdateValue(track, 'originalReleaseTrack'),
+        !CacheableObject.getUpdateValue(track, 'mainReleaseTrack'),
 
       // It's still necessary to check alwaysReferenceByDirectory here, since
       // it may be set manually (with `Always Reference By Directory: true`),
@@ -643,7 +691,12 @@ export class Track extends Thing {
     },
 
     trackWithArtwork: {
-      referenceTypes: ['track'],
+      referenceTypes: [
+        'track',
+        'track-referencing-artworks',
+        'track-referenced-artworks',
+      ],
+
       bindTo: 'trackData',
 
       include: track =>
@@ -654,32 +707,144 @@ export class Track extends Thing {
           ? []
           : [track.name]),
     },
+
+    trackPrimaryArtwork: {
+      [Thing.findThisThingOnly]: false,
+
+      referenceTypes: [
+        'track',
+        'track-referencing-artworks',
+        'track-referenced-artworks',
+      ],
+
+      bindTo: 'artworkData',
+
+      include: (artwork, {Artwork, Track}) =>
+        artwork instanceof Artwork &&
+        artwork.thing instanceof Track &&
+        artwork === artwork.thing.trackArtworks[0],
+
+      getMatchableNames: ({thing: track}) =>
+        (track.alwaysReferenceByDirectory
+          ? []
+          : [track.name]),
+
+      getMatchableDirectories: ({thing: track}) =>
+        [track.directory],
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    tracksWhichReference: {
+      bindTo: 'trackData',
+
+      referencing: track => track.isMainRelease ? [track] : [],
+      referenced: track => track.referencedTracks,
+    },
+
+    tracksWhichSample: {
+      bindTo: 'trackData',
+
+      referencing: track => track.isMainRelease ? [track] : [],
+      referenced: track => track.sampledTracks,
+    },
+
+    tracksWhoseArtworksFeature: {
+      bindTo: 'trackData',
+
+      referencing: track => [track],
+      referenced: track => track.artTags,
+    },
+
+    trackArtistContributionsBy:
+      soupyReverse.contributionsBy('trackData', 'artistContribs'),
+
+    trackContributorContributionsBy:
+      soupyReverse.contributionsBy('trackData', 'contributorContribs'),
+
+    trackCoverArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('trackData', 'trackArtworks'),
+
+    tracksWithCommentaryBy: {
+      bindTo: 'trackData',
+
+      referencing: track => [track],
+      referenced: track => track.commentatorArtists,
+    },
+
+    tracksWhichAreSecondaryReleasesOf: {
+      bindTo: 'trackData',
+
+      referencing: track => track.isSecondaryRelease ? [track] : [],
+      referenced: track => [track.mainReleaseTrack],
+    },
   };
 
   // Track YAML loading is handled in album.js.
   static [Thing.getYamlLoadingSpec] = null;
 
+  getOwnAdditionalFilePath(_file, filename) {
+    if (!this.album) return null;
+
+    return [
+      'media.albumAdditionalFile',
+      this.album.directory,
+      filename,
+    ];
+  }
+
+  getOwnArtworkPath(artwork) {
+    if (!this.album) return null;
+
+    return [
+      'media.trackCover',
+      this.album.directory,
+
+      (artwork.unqualifiedDirectory
+        ? this.directory + '-' + artwork.unqualifiedDirectory
+        : this.directory),
+
+      artwork.fileExtension,
+    ];
+  }
+
+  countOwnContributionInContributionTotals(_contrib) {
+    if (!this.countInArtistTotals) {
+      return false;
+    }
+
+    if (this.isSecondaryRelease) {
+      return false;
+    }
+
+    return true;
+  }
+
+  countOwnContributionInDurationTotals(_contrib) {
+    if (!this.countInArtistTotals) {
+      return false;
+    }
+
+    if (this.isSecondaryRelease) {
+      return false;
+    }
+
+    return true;
+  }
+
   [inspect.custom](depth) {
     const parts = [];
 
     parts.push(Thing.prototype[inspect.custom].apply(this));
 
-    if (CacheableObject.getUpdateValue(this, 'originalReleaseTrack')) {
-      parts.unshift(`${colors.yellow('[rerelease]')} `);
+    if (CacheableObject.getUpdateValue(this, 'mainReleaseTrack')) {
+      parts.unshift(`${colors.yellow('[secrelease]')} `);
     }
 
     let album;
 
     if (depth >= 0) {
-      try {
-        album = this.album;
-      } catch (_error) {
-        // Computing album might crash for any reason, which we don't want to
-        // distract from another error we might be trying to work out at the
-        // moment (for which debugging might involve inspecting this track!).
-      }
-
-      album ??= this.dataSourceAlbum;
+      album = this.album;
     }
 
     if (album) {
diff --git a/src/data/things/wiki-info.js b/src/data/things/wiki-info.js
index ef643681..f97f9027 100644
--- a/src/data/things/wiki-info.js
+++ b/src/data/things/wiki-info.js
@@ -1,9 +1,8 @@
 export const WIKI_INFO_FILE = 'wiki-info.yaml';
 
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
-import {parseContributionPresets} from '#yaml';
+import {parseContributionPresets, parseWallpaperParts} from '#yaml';
 
 import {
   isBoolean,
@@ -15,8 +14,17 @@ import {
 } from '#validators';
 
 import {exitWithoutDependency} from '#composite/control-flow';
-import {contentString, flag, name, referenceList, wikiData}
-  from '#composite/wiki-properties';
+
+import {
+  contentString,
+  fileExtension,
+  flag,
+  name,
+  referenceList,
+  simpleString,
+  soupyFind,
+  wallpaperParts,
+} from '#composite/wiki-properties';
 
 export class WikiInfo extends Thing {
   static [Thing.friendlyName] = `Wiki Info`;
@@ -69,10 +77,13 @@ export class WikiInfo extends Thing {
       },
     },
 
+    wikiWallpaperFileExtension: fileExtension('jpg'),
+    wikiWallpaperStyle: simpleString(),
+    wikiWallpaperParts: wallpaperParts(),
+
     divideTrackListsByGroups: referenceList({
       class: input.value(Group),
-      find: input.value(find.group),
-      data: 'groupData',
+      find: soupyFind.input('group'),
     }),
 
     contributionPresets: {
@@ -99,6 +110,8 @@ export class WikiInfo extends Thing {
 
     // Update only
 
+    find: soupyFind(),
+
     searchDataAvailable: {
       flags: {update: true},
       update: {
@@ -106,28 +119,40 @@ export class WikiInfo extends Thing {
         default: false,
       },
     },
-
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
   });
 
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Name': {property: 'name'},
       'Short Name': {property: 'nameShort'},
+
       'Color': {property: 'color'},
+
       'Description': {property: 'description'},
+
       'Footer Content': {property: 'footerContent'},
+
       'Default Language': {property: 'defaultLanguage'},
+
       'Canonical Base': {property: 'canonicalBase'},
-      'Divide Track Lists By Groups': {property: 'divideTrackListsByGroups'},
+
+      'Wiki Wallpaper File Extension': {property: 'wikiWallpaperFileExtension'},
+
+      'Wiki Wallpaper Style': {property: 'wikiWallpaperStyle'},
+
+      'Wiki Wallpaper Parts': {
+        property: 'wikiWallpaperParts',
+        transform: parseWallpaperParts,
+      },
+
       'Enable Flashes & Games': {property: 'enableFlashesAndGames'},
       'Enable Listings': {property: 'enableListings'},
       'Enable News': {property: 'enableNews'},
       'Enable Art Tag UI': {property: 'enableArtTagUI'},
       'Enable Group UI': {property: 'enableGroupUI'},
 
+      'Divide Track Lists By Groups': {property: 'divideTrackListsByGroups'},
+
       'Contribution Presets': {
         property: 'contributionPresets',
         transform: parseContributionPresets,
diff --git a/src/data/validators.js b/src/data/validators.js
deleted file mode 100644
index 84e08cb8..00000000
--- a/src/data/validators.js
+++ /dev/null
@@ -1,1104 +0,0 @@
-import {inspect as nodeInspect} from 'node:util';
-
-import {openAggregate, withAggregate} from '#aggregate';
-import {colors, ENABLE_COLOR} from '#cli';
-import {cut, empty, matchMultiline, typeAppearance} from '#sugar';
-import {commentaryRegexCaseInsensitive, commentaryRegexCaseSensitiveOneShot}
-  from '#wiki-data';
-
-function inspect(value) {
-  return nodeInspect(value, {colors: ENABLE_COLOR});
-}
-
-export function getValidatorCreator(validator) {
-  return validator[Symbol.for(`hsmusic.validator.creator`)] ?? null;
-}
-
-export function getValidatorCreatorMeta(validator) {
-  return validator[Symbol.for(`hsmusic.validator.creatorMeta`)] ?? null;
-}
-
-export function setValidatorCreatorMeta(validator, creator, meta) {
-  validator[Symbol.for(`hsmusic.validator.creator`)] = creator;
-  validator[Symbol.for(`hsmusic.validator.creatorMeta`)] = meta;
-  return validator;
-}
-
-// Basic types (primitives)
-
-export function a(noun) {
-  return /[aeiou]/.test(noun[0]) ? `an ${noun}` : `a ${noun}`;
-}
-
-export function validateType(type) {
-  const fn = value => {
-    if (typeof value !== type)
-      throw new TypeError(`Expected ${a(type)}, got ${typeAppearance(value)}`);
-
-    return true;
-  };
-
-  setValidatorCreatorMeta(fn, validateType, {type});
-
-  return fn;
-}
-
-export const isBoolean =
-  validateType('boolean');
-
-export const isFunction =
-  validateType('function');
-
-export const isNumber =
-  validateType('number');
-
-export const isString =
-  validateType('string');
-
-export const isSymbol =
-  validateType('symbol');
-
-// Use isObject instead, which disallows null.
-export const isTypeofObject =
-  validateType('object');
-
-export function isPositive(number) {
-  isNumber(number);
-
-  if (number <= 0) throw new TypeError(`Expected positive number`);
-
-  return true;
-}
-
-export function isNegative(number) {
-  isNumber(number);
-
-  if (number >= 0) throw new TypeError(`Expected negative number`);
-
-  return true;
-}
-
-export function isPositiveOrZero(number) {
-  isNumber(number);
-
-  if (number < 0) throw new TypeError(`Expected positive number or zero`);
-
-  return true;
-}
-
-export function isNegativeOrZero(number) {
-  isNumber(number);
-
-  if (number > 0) throw new TypeError(`Expected negative number or zero`);
-
-  return true;
-}
-
-export function isInteger(number) {
-  isNumber(number);
-
-  if (number % 1 !== 0) throw new TypeError(`Expected integer`);
-
-  return true;
-}
-
-export function isCountingNumber(number) {
-  isInteger(number);
-  isPositive(number);
-
-  return true;
-}
-
-export function isWholeNumber(number) {
-  isInteger(number);
-  isPositiveOrZero(number);
-
-  return true;
-}
-
-export function isStringNonEmpty(value) {
-  isString(value);
-
-  if (value.trim().length === 0)
-    throw new TypeError(`Expected non-empty string`);
-
-  return true;
-}
-
-export function optional(validator) {
-  return value =>
-    value === null ||
-    value === undefined ||
-    validator(value);
-}
-
-// Complex types (non-primitives)
-
-export function isInstance(value, constructor) {
-  isObject(value);
-
-  if (!(value instanceof constructor))
-    throw new TypeError(`Expected ${constructor.name}, got ${value.constructor.name}`);
-
-  return true;
-}
-
-export function isDate(value) {
-  isInstance(value, Date);
-
-  if (isNaN(value))
-    throw new TypeError(`Expected valid date`);
-
-  return true;
-}
-
-export function isObject(value) {
-  isTypeofObject(value);
-
-  // Note: Please remember that null is always a valid value for properties
-  // held by a CacheableObject. This assertion is exclusively for use in other
-  // contexts.
-  if (value === null)
-    throw new TypeError(`Expected an object, got null`);
-
-  return true;
-}
-
-export function isArray(value) {
-  if (typeof value !== 'object' || value === null || !Array.isArray(value))
-    throw new TypeError(`Expected an array, got ${typeAppearance(value)}`);
-
-  return true;
-}
-
-// This one's shaped a bit different from other "is" functions.
-// More like validate functions, it returns a function.
-export function is(...values) {
-  if (Array.isArray(values)) {
-    values = new Set(values);
-  }
-
-  if (values.size === 1) {
-    const expected = Array.from(values)[0];
-
-    return (value) => {
-      if (value !== expected) {
-        throw new TypeError(`Expected ${expected}, got ${value}`);
-      }
-
-      return true;
-    };
-  }
-
-  const fn = (value) => {
-    if (!values.has(value)) {
-      throw new TypeError(`Expected one of ${Array.from(values).join(' ')}, got ${value}`);
-    }
-
-    return true;
-  };
-
-  setValidatorCreatorMeta(fn, is, {values});
-
-  return fn;
-}
-
-function validateArrayItemsHelper(itemValidator) {
-  return (item, index, array) => {
-    try {
-      const value = itemValidator(item, index, array);
-
-      if (value !== true) {
-        throw new Error(`Expected validator to return true`);
-      }
-    } catch (caughtError) {
-      const indexPart = colors.yellow(`zero-index ${index}`)
-      const itemPart = inspect(item);
-      const message = `Error at ${indexPart}: ${itemPart}`;
-      const error = new Error(message, {cause: caughtError});
-      error[Symbol.for('hsmusic.annotateError.indexInSourceArray')] = index;
-      throw error;
-    }
-  };
-}
-
-export function validateArrayItems(itemValidator) {
-  const helper = validateArrayItemsHelper(itemValidator);
-
-  return (array) => {
-    isArray(array);
-
-    withAggregate({message: 'Errors validating array items'}, ({call}) => {
-      for (let index = 0; index < array.length; index++) {
-        call(helper, array[index], index, array);
-      }
-    });
-
-    return true;
-  };
-}
-
-export function strictArrayOf(itemValidator) {
-  return validateArrayItems(itemValidator);
-}
-
-export function sparseArrayOf(itemValidator) {
-  return validateArrayItems((item, index, array) => {
-    if (item === false || item === null) {
-      return true;
-    }
-
-    return itemValidator(item, index, array);
-  });
-}
-
-export function looseArrayOf(itemValidator) {
-  return validateArrayItems((item, index, array) => {
-    if (item === false || item === null || item === undefined) {
-      return true;
-    }
-
-    return itemValidator(item, index, array);
-  });
-}
-
-export function validateInstanceOf(constructor) {
-  const fn = (object) => isInstance(object, constructor);
-
-  setValidatorCreatorMeta(fn, validateInstanceOf, {constructor});
-
-  return fn;
-}
-
-// Wiki data (primitives & non-primitives)
-
-export function isColor(color) {
-  isStringNonEmpty(color);
-
-  if (color.startsWith('#')) {
-    if (![4, 5, 7, 9].includes(color.length))
-      throw new TypeError(`Expected #rgb, #rgba, #rrggbb, or #rrggbbaa, got length ${color.length}`);
-
-    if (/[^0-9a-fA-F]/.test(color.slice(1)))
-      throw new TypeError(`Expected hexadecimal digits`);
-
-    return true;
-  }
-
-  throw new TypeError(`Unknown color format`);
-}
-
-export function isCommentary(commentaryText) {
-  isContentString(commentaryText);
-
-  const rawMatches =
-    Array.from(commentaryText.matchAll(commentaryRegexCaseInsensitive));
-
-  if (empty(rawMatches)) {
-    throw new TypeError(`Expected at least one commentary heading`);
-  }
-
-  const niceMatches =
-    rawMatches.map(match => ({
-      position: match.index,
-      length: match[0].length,
-    }));
-
-  validateArrayItems(({position, length}, index) => {
-    if (index === 0 && position > 0) {
-      throw new TypeError(`Expected first commentary heading to be at top`);
-    }
-
-    const ownInput = commentaryText.slice(position, position + length);
-    const restOfInput = commentaryText.slice(position + length);
-
-    const upToNextLineBreak =
-      (restOfInput.includes('\n')
-        ? restOfInput.slice(0, restOfInput.indexOf('\n'))
-        : restOfInput);
-
-    if (/\S/.test(upToNextLineBreak)) {
-      throw new TypeError(
-        `Expected commentary heading to occupy entire line, got extra text:\n` +
-        `${colors.green(`"${cut(ownInput, 40)}"`)} (<- heading)\n` +
-        `(extra on same line ->) ${colors.red(`"${cut(upToNextLineBreak, 30)}"`)}\n` +
-        `(Check for missing "|-" in YAML, or a misshapen annotation)`);
-    }
-
-    if (!commentaryRegexCaseSensitiveOneShot.test(ownInput)) {
-      throw new TypeError(
-        `Miscapitalization in commentary heading:\n` +
-        `${colors.red(`"${cut(ownInput, 60)}"`)}\n` +
-        `(Check for ${colors.red(`"<I>"`)} instead of ${colors.green(`"<i>"`)})`);
-    }
-
-    const nextHeading =
-      (index === niceMatches.length - 1
-        ? commentaryText.length
-        : niceMatches[index + 1].position);
-
-    const upToNextHeading =
-      commentaryText.slice(position + length, nextHeading);
-
-    if (!/\S/.test(upToNextHeading)) {
-      throw new TypeError(
-        `Expected commentary entry to have body text, only got a heading`);
-    }
-
-    return true;
-  })(niceMatches);
-
-  return true;
-}
-
-const isArtistRef = validateReference('artist');
-
-export function validateProperties(spec) {
-  const {
-    [validateProperties.validateOtherKeys]: validateOtherKeys = null,
-    [validateProperties.allowOtherKeys]: allowOtherKeys = false,
-  } = spec;
-
-  const specEntries = Object.entries(spec);
-  const specKeys = Object.keys(spec);
-
-  return (object) => {
-    isObject(object);
-
-    if (Array.isArray(object))
-      throw new TypeError(`Expected an object, got array`);
-
-    withAggregate({message: `Errors validating object properties`}, ({push}) => {
-      const testEntries = specEntries.slice();
-
-      const unknownKeys = Object.keys(object).filter((key) => !specKeys.includes(key));
-      if (validateOtherKeys) {
-        for (const key of unknownKeys) {
-          testEntries.push([key, validateOtherKeys]);
-        }
-      }
-
-      for (const [specKey, specValidator] of testEntries) {
-        const value = object[specKey];
-        try {
-          specValidator(value);
-        } catch (caughtError) {
-          const keyPart = colors.green(specKey);
-          const valuePart = inspect(value);
-          const message = `Error for key ${keyPart}: ${valuePart}`;
-          push(new Error(message, {cause: caughtError}));
-        }
-      }
-
-      if (!validateOtherKeys && !allowOtherKeys && !empty(unknownKeys)) {
-        push(new Error(
-          `Unknown keys present (${unknownKeys.length}): [${unknownKeys.join(', ')}]`));
-      }
-    });
-
-    return true;
-  };
-}
-
-validateProperties.validateOtherKeys = Symbol();
-validateProperties.allowOtherKeys = Symbol();
-
-export const validateAllPropertyValues = (validator) =>
-  validateProperties({
-    [validateProperties.validateOtherKeys]: validator,
-  });
-
-const illeaglInvisibleSpace = {
-  action: 'delete',
-};
-
-const illegalVisibleSpace = {
-  action: 'replace',
-  with: ' ',
-  withAnnotation: `normal space`,
-};
-
-const illegalContentSpec = [
-  {illegal: '\u200b', annotation: `zero-width space`, ...illeaglInvisibleSpace},
-  {illegal: '\u2005', annotation: `four-per-em space`, ...illegalVisibleSpace},
-  {illegal: '\u205f', annotation: `medium mathematical space`, ...illegalVisibleSpace},
-  {illegal: '\xa0', annotation: `non-breaking space`, ...illegalVisibleSpace},
-
-  {
-    action: 'replace',
-    illegal: '<a href',
-    annotation: `HTML-style link`,
-    with: '[...](...)',
-    withAnnotation: `markdown`,
-  },
-];
-
-for (const entry of illegalContentSpec) {
-  entry.test = string =>
-    string.startsWith(entry.illegal);
-
-  if (entry.action === 'replace') {
-    entry.enact = string =>
-      string.replaceAll(entry.illegal, entry.with);
-  }
-}
-
-const illegalSequencesInContent =
-  illegalContentSpec
-    .map(entry => entry.illegal)
-    .map(illegal =>
-      (illegal.length === 1
-        ? `${illegal}+`
-        : `(?:${illegal})+`))
-    .join('|');
-
-const illegalContentRegexp =
-  new RegExp(illegalSequencesInContent, 'g');
-
-const legalContentNearEndRegexp =
-  new RegExp(`(?<=^|${illegalSequencesInContent})(?:(?!${illegalSequencesInContent}).)+$`);
-
-const legalContentNearStartRegexp =
-  new RegExp(`^(?:(?!${illegalSequencesInContent}).)+`);
-
-const trimWhitespaceNearBothSidesRegexp =
-  /^ +| +$/gm;
-
-const trimWhitespaceNearEndRegexp =
-  / +$/gm;
-
-export function isContentString(content) {
-  isString(content);
-
-  const mainAggregate = openAggregate({
-    message: `Errors validating content string`,
-    translucent: 'single',
-  });
-
-  const illegalAggregate = openAggregate({
-    message: `Illegal characters found in content string`,
-  });
-
-  for (const {match, where} of matchMultiline(content, illegalContentRegexp)) {
-    const {annotation, action, ...options} =
-      illegalContentSpec
-        .find(entry => entry.test(match[0]));
-
-    const matchStart = match.index;
-    const matchEnd = match.index + match[0].length;
-
-    const before =
-      content
-        .slice(Math.max(0, matchStart - 3), matchStart)
-        .match(legalContentNearEndRegexp)
-        ?.[0];
-
-    const after =
-      content
-        .slice(matchEnd, Math.min(content.length, matchEnd + 3))
-        .match(legalContentNearStartRegexp)
-        ?.[0];
-
-    const beforePart =
-      before && `"${before}"`;
-
-    const afterPart =
-      after && `"${after}"`;
-
-    const surroundings =
-      (before && after
-        ? `between ${beforePart} and ${afterPart}`
-     : before
-        ? `after ${beforePart}`
-     : after
-        ? `before ${afterPart}`
-        : ``);
-
-    const illegalPart =
-      colors.red(
-        (annotation
-          ? `"${match[0]}" (${annotation})`
-          : `"${match[0]}"`));
-
-    const replacement =
-      (action === 'replace'
-        ? options.enact(match[0])
-        : null);
-
-    const replaceWithPart =
-      (action === 'replace'
-        ? colors.green(
-            (options.withAnnotation
-              ? `"${replacement}" (${options.withAnnotation})`
-              : `"${replacement}"`))
-        : null);
-
-    const actionPart =
-      (action === `delete`
-        ? `Delete ${illegalPart}`
-     : action === 'replace'
-        ? `Replace ${illegalPart} with ${replaceWithPart}`
-        : `Matched ${illegalPart}`);
-
-    const parts = [
-      actionPart,
-      surroundings,
-      `(${where})`,
-    ].filter(Boolean);
-
-    illegalAggregate.push(new TypeError(parts.join(` `)));
-  }
-
-  const isMultiline = content.includes('\n');
-
-  const trimWhitespaceAggregate = openAggregate({
-    message:
-      (isMultiline
-        ? `Whitespace found at end of line`
-        : `Whitespace found at start or end`),
-  });
-
-  const trimWhitespaceRegexp =
-    (isMultiline
-      ? trimWhitespaceNearEndRegexp
-      : trimWhitespaceNearBothSidesRegexp);
-
-  for (
-    const {match, lineNumber, columnNumber, containingLine} of
-    matchMultiline(content, trimWhitespaceRegexp, {
-      formatWhere: false,
-      getContainingLine: true,
-    })
-  ) {
-    const linePart =
-      colors.yellow(`line ${lineNumber + 1}`);
-
-    const where =
-      (match[0].length === containingLine.length
-        ? `as all of ${linePart}`
-     : columnNumber === 0
-        ? (isMultiline
-            ? `at start of ${linePart}`
-            : `at start`)
-        : (isMultiline
-            ? `at end of ${linePart}`
-            : `at end`));
-
-    const whitespacePart =
-      colors.red(`"${match[0]}"`);
-
-    const parts = [
-      `Matched ${whitespacePart}`,
-      where,
-    ];
-
-    trimWhitespaceAggregate.push(new TypeError(parts.join(` `)));
-  }
-
-  mainAggregate.call(() => illegalAggregate.close());
-  mainAggregate.call(() => trimWhitespaceAggregate.close());
-  mainAggregate.close();
-
-  return true;
-}
-
-export function isThingClass(thingClass) {
-  isFunction(thingClass);
-
-  // This is *expressly* no faster than an instanceof check, because it's
-  // deliberately still walking the prototype chain for the provided object.
-  // (This is necessary because the symbol we're checking is defined only on
-  // the Thing constructor, and not directly on each subclass.) However, it's
-  // preferred over an instanceof check anyway, because instanceof would
-  // require that the #validators module has access to #thing, which it
-  // currently doesn't!
-  if (!(Symbol.for('Thing.isThingConstructor') in thingClass)) {
-    throw new TypeError(`Expected a Thing constructor, missing Thing.isThingConstructor`);
-  }
-
-  return true;
-}
-
-export function isThing(thing) {
-  isObject(thing);
-
-  // This *is* faster than an instanceof check, because it doesn't walk the
-  // prototype chain. It works because this property is set as part of every
-  // Thing subclass's inherited "public class fields" - it's set directly on
-  // every constructed Thing.
-  if (!Object.hasOwn(thing, Symbol.for('Thing.isThing'))) {
-    throw new TypeError(`Expected a Thing, missing Thing.isThing`);
-  }
-
-  return true;
-}
-
-export const isContribution = validateProperties({
-  artist: isArtistRef,
-  annotation: optional(isStringNonEmpty),
-
-  countInDurationTotals: optional(isBoolean),
-  countInContributionTotals: optional(isBoolean),
-});
-
-export const isContributionList = validateArrayItems(isContribution);
-
-export const contributionPresetPropertySpec = {
-  album: [
-    'artistContribs',
-  ],
-
-  flash: [
-    'contributorContribs',
-  ],
-
-  track: [
-    'artistContribs',
-    'contributorContribs',
-  ],
-};
-
-// TODO: This validator basically constructs itself as it goes.
-// This is definitely some shenanigans!
-export function isContributionPresetContext(list) {
-  isArray(list);
-
-  if (empty(list)) {
-    throw new TypeError(`Expected at least one item`);
-  }
-
-  const isTarget =
-    is(...Object.keys(contributionPresetPropertySpec));
-
-  const [target, ...properties] = list;
-
-  isTarget(target);
-
-  const isProperty =
-    is(...contributionPresetPropertySpec[target]);
-
-  const isPropertyList =
-    validateArrayItems(isProperty);
-
-  isPropertyList(properties);
-
-  return true;
-}
-
-export const isContributionPreset = validateProperties({
-  annotation: isStringNonEmpty,
-  context: isContributionPresetContext,
-
-  countInDurationTotals: optional(isBoolean),
-  countInContributionTotals: optional(isBoolean),
-});
-
-export const isContributionPresetList = validateArrayItems(isContributionPreset);
-
-export const isAdditionalFile = validateProperties({
-  title: isName,
-  description: optional(isContentString),
-  files: optional(validateArrayItems(isString)),
-});
-
-export const isAdditionalFileList = validateArrayItems(isAdditionalFile);
-
-export const isTrackSection = validateProperties({
-  name: optional(isName),
-  color: optional(isColor),
-  dateOriginallyReleased: optional(isDate),
-  isDefaultTrackSection: optional(isBoolean),
-  tracks: optional(validateReferenceList('track')),
-});
-
-export const isTrackSectionList = validateArrayItems(isTrackSection);
-
-export const isSeries = validateProperties({
-  name: isName,
-  description: optional(isContentString),
-  albums: optional(validateReferenceList('album')),
-
-  showAlbumArtists:
-    optional(is('all', 'differing', 'none')),
-});
-
-export const isSeriesList = validateArrayItems(isSeries);
-
-export const isWallpaperPart = validateProperties({
-  asset: optional(isString),
-  style: optional(isString),
-});
-
-export const isWallpaperPartList = validateArrayItems(isWallpaperPart);
-
-export function isDimensions(dimensions) {
-  isArray(dimensions);
-
-  if (dimensions.length !== 2) throw new TypeError(`Expected 2 item array`);
-
-  if (dimensions[0] !== null) {
-    isPositive(dimensions[0]);
-    isInteger(dimensions[0]);
-  }
-
-  if (dimensions[1] !== null) {
-    isPositive(dimensions[1]);
-    isInteger(dimensions[1]);
-  }
-
-  return true;
-}
-
-export function isDirectory(directory) {
-  isStringNonEmpty(directory);
-
-  if (directory.match(/[^a-zA-Z0-9_-]/))
-    throw new TypeError(`Expected only letters, numbers, dash, and underscore, got "${directory}"`);
-
-  return true;
-}
-
-export function isDuration(duration) {
-  isNumber(duration);
-  isPositiveOrZero(duration);
-
-  return true;
-}
-
-export function isFileExtension(string) {
-  isStringNonEmpty(string);
-
-  if (string[0] === '.')
-    throw new TypeError(`Expected no dot (.) at the start of file extension`);
-
-  if (string.match(/[^a-zA-Z0-9_]/))
-    throw new TypeError(`Expected only alphanumeric and underscore`);
-
-  return true;
-}
-
-export function isLanguageCode(string) {
-  // TODO: This is a stub function because really we don't need a detailed
-  // is-language-code parser right now.
-
-  isString(string);
-
-  return true;
-}
-
-export function isName(name) {
-  return isContentString(name);
-}
-
-export function isURL(string) {
-  isStringNonEmpty(string);
-
-  new URL(string);
-
-  return true;
-}
-
-export function validateReference(type) {
-  return (ref) => {
-    isStringNonEmpty(ref);
-
-    const match = ref
-      .trim()
-      .match(/^(?:(?<typePart>\S+):(?=\S))?(?<directoryPart>.+)(?<!:)$/);
-
-    if (!match) throw new TypeError(`Malformed reference`);
-
-    const {groups: {typePart, directoryPart}} = match;
-
-    if (typePart) {
-      if (Array.isArray(type)) {
-        if (!type.includes(typePart)) {
-          throw new TypeError(
-            `Expected ref to begin with one of ` +
-            type.map(type => `"${type}:"`).join(', ') +
-            `, got "${typePart}:"`);
-        }
-      } else if (typePart !== type) {
-        throw new TypeError(
-          `Expected ref to begin with "${type}:", got "${typePart}:"`);
-      }
-
-      isDirectory(directoryPart);
-    }
-
-    isName(ref);
-
-    return true;
-  };
-}
-
-export function validateReferenceList(type) {
-  return validateArrayItems(validateReference(type));
-}
-
-export function validateThing({
-  referenceType: expectedReferenceType = '',
-} = {}) {
-  return (thing) => {
-    isThing(thing);
-
-    if (expectedReferenceType) {
-      const {[Symbol.for('Thing.referenceType')]: referenceType} =
-        thing.constructor;
-
-      if (referenceType !== expectedReferenceType) {
-        throw new TypeError(`Expected only ${expectedReferenceType}, got other type: ${referenceType}`);
-      }
-    }
-
-    return true;
-  };
-}
-
-const validateWikiData_cache = {};
-
-export function validateWikiData({
-  referenceType = '',
-  allowMixedTypes = false,
-} = {}) {
-  if (referenceType && allowMixedTypes) {
-    throw new TypeError(`Don't specify both referenceType and allowMixedTypes`);
-  }
-
-  validateWikiData_cache[referenceType] ??= {};
-  validateWikiData_cache[referenceType][allowMixedTypes] ??= new WeakMap();
-
-  const isArrayOfObjects = validateArrayItems(isObject);
-
-  return (array) => {
-    const subcache = validateWikiData_cache[referenceType][allowMixedTypes];
-    if (subcache.has(array)) return subcache.get(array);
-
-    let OK = false;
-
-    try {
-      isArrayOfObjects(array);
-
-      if (empty(array)) {
-        OK = true; return true;
-      }
-
-      const allRefTypes = new Set();
-
-      let foundThing = false;
-      let foundOtherObject = false;
-
-      for (const object of array) {
-        if (Object.hasOwn(object, Symbol.for('Thing.isThing'))) {
-          // Early-exit if a non-Thing object has been found - nothing more can
-          // be learned.
-          if (foundOtherObject) {
-            throw new TypeError(`Expected array of wiki data objects, got mixed items`);
-          }
-
-          foundThing = true;
-          allRefTypes.add(object.constructor[Symbol.for('Thing.referenceType')]);
-        } else {
-          // Early-exit if a Thing has been found - nothing more can be learned.
-          if (foundThing) {
-            throw new TypeError(`Expected array of wiki data objects, got mixed items`);
-          }
-
-          foundOtherObject = true;
-        }
-      }
-
-      if (foundOtherObject && !foundThing) {
-        throw new TypeError(`Expected array of wiki data objects, got array of other objects`);
-      }
-
-      if (allRefTypes.size > 1) {
-        if (allowMixedTypes) {
-          OK = true; return true;
-        }
-
-        const types = () => Array.from(allRefTypes).join(', ');
-
-        if (referenceType) {
-          if (allRefTypes.has(referenceType)) {
-            allRefTypes.remove(referenceType);
-            throw new TypeError(`Expected array of only ${referenceType}, also got other types: ${types()}`)
-          } else {
-            throw new TypeError(`Expected array of only ${referenceType}, got other types: ${types()}`);
-          }
-        }
-
-        throw new TypeError(`Expected array of unmixed reference types, got multiple: ${types()}`);
-      }
-
-      const onlyRefType = Array.from(allRefTypes)[0];
-
-      if (referenceType && onlyRefType !== referenceType) {
-        throw new TypeError(`Expected array of ${referenceType}, got array of ${onlyRefType}`)
-      }
-
-      OK = true; return true;
-    } finally {
-      subcache.set(array, OK);
-    }
-  };
-}
-
-export const isAdditionalName = validateProperties({
-  name: isContentString,
-  annotation: optional(isContentString),
-});
-
-export const isAdditionalNameList = validateArrayItems(isAdditionalName);
-
-// Compositional utilities
-
-export function anyOf(...validators) {
-  const validConstants = new Set();
-  const validConstructors = new Set();
-  const validTypes = new Set();
-
-  const constantValidators = [];
-  const constructorValidators = [];
-  const typeValidators = [];
-
-  const leftoverValidators = [];
-
-  for (const validator of validators) {
-    const creator = getValidatorCreator(validator);
-    const creatorMeta = getValidatorCreatorMeta(validator);
-
-    switch (creator) {
-      case is:
-        for (const value of creatorMeta.values) {
-          validConstants.add(value);
-        }
-
-        constantValidators.push(validator);
-        break;
-
-      case validateInstanceOf:
-        validConstructors.add(creatorMeta.constructor);
-        constructorValidators.push(validator);
-        break;
-
-      case validateType:
-        validTypes.add(creatorMeta.type);
-        typeValidators.push(validator);
-        break;
-
-      default:
-        leftoverValidators.push(validator);
-        break;
-    }
-  }
-
-  return (value) => {
-    const errorInfo = [];
-
-    if (validConstants.has(value)) {
-      return true;
-    }
-
-    if (!empty(validTypes)) {
-      if (validTypes.has(typeof value)) {
-        return true;
-      }
-    }
-
-    for (const constructor of validConstructors) {
-      if (value instanceof constructor) {
-        return true;
-      }
-    }
-
-    for (const [i, validator] of leftoverValidators.entries()) {
-      try {
-        const result = validator(value);
-
-        if (result !== true) {
-          throw new Error(`Check returned false`);
-        }
-
-        return true;
-      } catch (error) {
-        errorInfo.push([validator, i, error]);
-      }
-    }
-
-    // Don't process error messages until every validator has failed.
-
-    const errors = [];
-    const prefaceErrorInfo = [];
-
-    let offset = 0;
-
-    if (!empty(validConstants)) {
-      const constants =
-        Array.from(validConstants);
-
-      const gotPart = `, got ${value}`;
-
-      prefaceErrorInfo.push([
-        constantValidators,
-        offset++,
-        new TypeError(
-          `Expected any of ${constants.join(' ')}` + gotPart),
-      ]);
-    }
-
-    if (!empty(validTypes)) {
-      const types =
-        Array.from(validTypes);
-
-      const gotType = typeAppearance(value);
-      const gotPart = `, got ${gotType}`;
-
-      prefaceErrorInfo.push([
-        typeValidators,
-        offset++,
-        new TypeError(
-          `Expected any of ${types.join(', ')}` + gotPart),
-      ]);
-    }
-
-    if (!empty(validConstructors)) {
-      const names =
-        Array.from(validConstructors)
-          .map(constructor => constructor.name);
-
-      const gotName = value?.constructor?.name;
-      const gotPart = (gotName ? `, got ${gotName}` : ``);
-
-      prefaceErrorInfo.push([
-        constructorValidators,
-        offset++,
-        new TypeError(
-          `Expected any of ${names.join(', ')}` + gotPart),
-      ]);
-    }
-
-    for (const info of errorInfo) {
-      info[1] += offset;
-    }
-
-    for (const [validator, i, error] of prefaceErrorInfo.concat(errorInfo)) {
-      error.message =
-        (validator?.name
-          ? `${i + 1}. "${validator.name}": ${error.message}`
-          : `${i + 1}. ${error.message}`);
-
-      error.check =
-        (Array.isArray(validator) && validator.length === 1
-          ? validator[0]
-          : validator);
-
-      errors.push(error);
-    }
-
-    const total = offset + leftoverValidators.length;
-    throw new AggregateError(errors,
-      `Expected any of ${total} possible checks, ` +
-      `but none were true`);
-  };
-}
diff --git a/src/data/yaml.js b/src/data/yaml.js
index 64223662..9a0295b8 100644
--- a/src/data/yaml.js
+++ b/src/data/yaml.js
@@ -8,11 +8,14 @@ import {inspect as nodeInspect} from 'node:util';
 import yaml from 'js-yaml';
 
 import {colors, ENABLE_COLOR, logInfo, logWarn} from '#cli';
+import {parseContentNodes, splitContentNodesAround} from '#replacer';
 import {sortByName} from '#sort';
 import Thing from '#thing';
 import thingConstructors from '#things';
+import {matchContentEntries, multipleLyricsDetectionRegex} from '#wiki-data';
 
 import {
+  aggregateThrows,
   annotateErrorWithFile,
   decorateErrorWithIndex,
   decorateErrorWithAnnotation,
@@ -30,8 +33,10 @@ import {
   atOffset,
   empty,
   filterProperties,
+  getNestedProp,
   stitchArrays,
   typeAppearance,
+  unique,
   withEntries,
 } from '#sugar';
 
@@ -86,6 +91,10 @@ function makeProcessDocument(thingConstructor, {
   // A or B.
   //
   invalidFieldCombinations = [],
+
+  // Bouncing function used to process subdocuments: this is a function which
+  // in turn calls the appropriate *result of* makeProcessDocument.
+  processDocument: bouncer,
 }) {
   if (!thingConstructor) {
     throw new Error(`Missing Thing class`);
@@ -95,6 +104,10 @@ function makeProcessDocument(thingConstructor, {
     throw new Error(`Expected fields to be provided`);
   }
 
+  if (!bouncer) {
+    throw new Error(`Missing processDocument bouncer`);
+  }
+
   const knownFields = Object.keys(fieldSpecs);
 
   const ignoredFields =
@@ -142,9 +155,12 @@ function makeProcessDocument(thingConstructor, {
         : `document`);
 
     const aggregate = openAggregate({
+      ...aggregateThrows(ProcessDocumentError),
       message: `Errors processing ${constructorPart}` + namePart,
     });
 
+    const thing = Reflect.construct(thingConstructor, []);
+
     const documentEntries = Object.entries(document)
       .filter(([field]) => !ignoredFields.includes(field));
 
@@ -192,13 +208,50 @@ function makeProcessDocument(thingConstructor, {
 
     const fieldValues = {};
 
+    const subdocSymbol = Symbol('subdoc');
+    const subdocLayouts = {};
+
+    const isSubdocToken = value =>
+      typeof value === 'object' &&
+      value !== null &&
+      Object.hasOwn(value, subdocSymbol);
+
+    const transformUtilities = {
+      ...thingConstructors,
+
+      subdoc(documentType, data, {
+        bindInto = null,
+        provide = null,
+      } = {}) {
+        if (!documentType)
+          throw new Error(`Expected document type, got ${typeAppearance(documentType)}`);
+        if (!data)
+          throw new Error(`Expected data, got ${typeAppearance(data)}`);
+        if (typeof data !== 'object' || data === null)
+          throw new Error(`Expected data to be an object, got ${typeAppearance(data)}`);
+        if (typeof bindInto !== 'string' && bindInto !== null)
+          throw new Error(`Expected bindInto to be a string, got ${typeAppearance(bindInto)}`);
+        if (typeof provide !== 'object' && provide !== null)
+          throw new Error(`Expected provide to be an object, got ${typeAppearance(provide)}`);
+
+        return {
+          [subdocSymbol]: {
+            documentType,
+            data,
+            bindInto,
+            provide,
+          },
+        };
+      },
+    };
+
     for (const [field, documentValue] of documentEntries) {
       if (skippedFields.has(field)) continue;
 
       // This variable would like to certify itself as "not into capitalism".
       let propertyValue =
         (fieldSpecs[field].transform
-          ? fieldSpecs[field].transform(documentValue)
+          ? fieldSpecs[field].transform(documentValue, transformUtilities)
           : documentValue);
 
       // Completely blank items in a YAML list are read as null.
@@ -221,10 +274,99 @@ function makeProcessDocument(thingConstructor, {
         }
       }
 
+      if (isSubdocToken(propertyValue)) {
+        subdocLayouts[field] = propertyValue[subdocSymbol];
+        continue;
+      }
+
+      if (Array.isArray(propertyValue) && propertyValue.every(isSubdocToken)) {
+        subdocLayouts[field] =
+          propertyValue
+            .map(token => token[subdocSymbol]);
+        continue;
+      }
+
       fieldValues[field] = propertyValue;
     }
 
-    const thing = Reflect.construct(thingConstructor, []);
+    const subdocErrors = [];
+
+    const followSubdocSetup = setup => {
+      let error = null;
+
+      let subthing;
+      try {
+        const result = bouncer(setup.data, setup.documentType);
+        subthing = result.thing;
+        result.aggregate.close();
+      } catch (caughtError) {
+        error = caughtError;
+      }
+
+      if (subthing) {
+        if (setup.bindInto) {
+          subthing[setup.bindInto] = thing;
+        }
+
+        if (setup.provide) {
+          Object.assign(subthing, setup.provide);
+        }
+      }
+
+      return {error, subthing};
+    };
+
+    for (const [field, layout] of Object.entries(subdocLayouts)) {
+      if (Array.isArray(layout)) {
+        const subthings = [];
+        let anySucceeded = false;
+        let anyFailed = false;
+
+        for (const [index, setup] of layout.entries()) {
+          const {subthing, error} = followSubdocSetup(setup);
+          if (error) {
+            subdocErrors.push(new SubdocError(
+              {field, index},
+              setup,
+              {cause: error}));
+          }
+
+          if (subthing) {
+            subthings.push(subthing);
+            anySucceeded = true;
+          } else {
+            anyFailed = true;
+          }
+        }
+
+        if (anySucceeded) {
+          fieldValues[field] = subthings;
+        } else if (anyFailed) {
+          skippedFields.add(field);
+        }
+      } else {
+        const setup = layout;
+        const {subthing, error} = followSubdocSetup(setup);
+
+        if (error) {
+          subdocErrors.push(new SubdocError(
+            {field},
+            setup,
+            {cause: error}));
+        }
+
+        if (subthing) {
+          fieldValues[field] = subthing;
+        } else {
+          skippedFields.add(field);
+        }
+      }
+    }
+
+    if (!empty(subdocErrors)) {
+      aggregate.push(new SubdocAggregateError(
+        subdocErrors, thingConstructor));
+    }
 
     const fieldValueErrors = [];
 
@@ -258,6 +400,8 @@ function makeProcessDocument(thingConstructor, {
   });
 }
 
+export class ProcessDocumentError extends AggregateError {}
+
 export class UnknownFieldsError extends Error {
   constructor(fields) {
     super(`Unknown fields ignored: ${fields.map(field => colors.red(field)).join(', ')}`);
@@ -345,12 +489,46 @@ export class SkippedFieldsSummaryError extends Error {
         : `${entries.length} fields`);
 
     super(
-      colors.bright(colors.yellow(`Altogether, skipped ${numFieldsText}:\n`)) +
+      colors.bright(colors.yellow(`Altogether, skipped ${numFieldsText}:`)) + '\n' +
       lines.join('\n') + '\n' +
       colors.bright(colors.yellow(`See above errors for details.`)));
   }
 }
 
+export class SubdocError extends Error {
+  constructor({field, index = null}, setup, options) {
+    const fieldText =
+      (index === null
+        ? colors.green(`"${field}"`)
+        : colors.yellow(`#${index + 1}`) + ' in ' +
+          colors.green(`"${field}"`));
+
+    const constructorText =
+      setup.documentType.name;
+
+    if (options.cause instanceof ProcessDocumentError) {
+      options.cause[Symbol.for('hsmusic.aggregate.translucent')] = true;
+    }
+
+    super(
+      `Errors processing ${constructorText} for ${fieldText} field`,
+      options);
+  }
+}
+
+export class SubdocAggregateError extends AggregateError {
+  [Symbol.for('hsmusic.aggregate.translucent')] = true;
+
+  constructor(errors, thingConstructor) {
+    const constructorText =
+      colors.green(thingConstructor.name);
+
+    super(
+      errors,
+      `Errors processing subdocuments for ${constructorText}`);
+  }
+}
+
 export function parseDate(date) {
   return new Date(date);
 }
@@ -433,49 +611,39 @@ export function parseContributors(entries) {
   });
 }
 
-export function parseAdditionalFiles(entries) {
+export function parseAdditionalFiles(entries, {subdoc, AdditionalFile}) {
   return parseArrayEntries(entries, item => {
     if (typeof item !== 'object') return item;
 
-    return {
-      title: item['Title'],
-      description: item['Description'] ?? null,
-      files: item['Files'],
-    };
+    return subdoc(AdditionalFile, item, {bindInto: 'thing'});
   });
 }
 
-export function parseAdditionalNames(entries) {
+export function parseAdditionalNames(entries, {subdoc, AdditionalName}) {
   return parseArrayEntries(entries, item => {
-    if (typeof item === 'object' && typeof item['Name'] === 'string')
-      return {
-        name: item['Name'],
-        annotation: item['Annotation'] ?? null,
-      };
+    if (typeof item === 'object') {
+      return subdoc(AdditionalName, item, {bindInto: 'thing'});
+    }
 
     if (typeof item !== 'string') return item;
 
     const match = item.match(extractAccentRegex);
     if (!match) return item;
 
-    return {
-      name: match.groups.main,
-      annotation: match.groups.accent ?? null,
+    const document = {
+      ['Name']: match.groups.main,
+      ['Annotation']: match.groups.accent ?? null,
     };
+
+    return subdoc(AdditionalName, document, {bindInto: 'thing'});
   });
 }
 
-export function parseSerieses(entries) {
+export function parseSerieses(entries, {subdoc, Series}) {
   return parseArrayEntries(entries, item => {
     if (typeof item !== 'object') return item;
 
-    return {
-      name: item['Name'],
-      description: item['Description'] ?? null,
-      albums: item['Albums'] ?? null,
-
-      showAlbumArtists: item['Show Album Artists'] ?? null,
-    };
+    return subdoc(Series, item, {bindInto: 'group'});
   });
 }
 
@@ -613,6 +781,172 @@ export function parseAnnotatedReferences(entries, {
   });
 }
 
+export function parseArtwork({
+  single = false,
+  thingProperty = null,
+  dimensionsFromThingProperty = null,
+  fileExtensionFromThingProperty = null,
+  dateFromThingProperty = null,
+  artistContribsFromThingProperty = null,
+  artistContribsArtistProperty = null,
+  artTagsFromThingProperty = null,
+  referencedArtworksFromThingProperty = null,
+}) {
+  const provide = {
+    thingProperty,
+    dimensionsFromThingProperty,
+    fileExtensionFromThingProperty,
+    dateFromThingProperty,
+    artistContribsFromThingProperty,
+    artistContribsArtistProperty,
+    artTagsFromThingProperty,
+    referencedArtworksFromThingProperty,
+  };
+
+  const parseSingleEntry = (entry, {subdoc, Artwork}) =>
+    subdoc(Artwork, entry, {bindInto: 'thing', provide});
+
+  const transform = (value, ...args) =>
+    (Array.isArray(value)
+      ? value.map(entry => parseSingleEntry(entry, ...args))
+   : single
+      ? parseSingleEntry(value, ...args)
+      : [parseSingleEntry(value, ...args)]);
+
+  transform.provide = provide;
+
+  return transform;
+}
+
+export function parseContentEntriesFromSourceText(thingClass, sourceText, {subdoc}) {
+  function map(matchEntry) {
+    let artistText = null, artistReferences = null;
+
+    const artistTextNodes =
+      Array.from(
+        splitContentNodesAround(
+          parseContentNodes(matchEntry.artistText),
+          /\|/g));
+
+    const separatorIndices =
+      artistTextNodes
+        .filter(node => node.type === 'separator')
+        .map(node => artistTextNodes.indexOf(node));
+
+    if (empty(separatorIndices)) {
+      if (artistTextNodes.length === 1 && artistTextNodes[0].type === 'text') {
+        artistReferences = matchEntry.artistText;
+      } else {
+        artistText = matchEntry.artistText;
+      }
+    } else {
+      const firstSeparatorIndex =
+        separatorIndices.at(0);
+
+      const secondSeparatorIndex =
+        separatorIndices.at(1) ??
+        artistTextNodes.length;
+
+      artistReferences =
+        matchEntry.artistText.slice(
+          artistTextNodes.at(0).i,
+          artistTextNodes.at(firstSeparatorIndex - 1).iEnd);
+
+      artistText =
+        matchEntry.artistText.slice(
+          artistTextNodes.at(firstSeparatorIndex).iEnd,
+          artistTextNodes.at(secondSeparatorIndex - 1).iEnd);
+    }
+
+    if (artistReferences) {
+      artistReferences =
+        artistReferences
+          .split(',')
+          .map(ref => ref.trim());
+    }
+
+    return {
+      'Artists':
+        artistReferences,
+
+      'Artist Text':
+        artistText,
+
+      'Annotation':
+        matchEntry.annotation,
+
+      'Date':
+        matchEntry.date,
+
+      'Second Date':
+        matchEntry.secondDate,
+
+      'Date Kind':
+        matchEntry.dateKind,
+
+      'Access Date':
+        matchEntry.accessDate,
+
+      'Access Kind':
+        matchEntry.accessKind,
+
+      'Body':
+        matchEntry.body,
+    };
+  }
+
+  const documents =
+    matchContentEntries(sourceText)
+      .map(matchEntry =>
+        withEntries(
+          map(matchEntry),
+          entries => entries
+            .filter(([key, value]) =>
+              value !== undefined &&
+              value !== null)));
+
+  const subdocs =
+    documents.map(document =>
+      subdoc(thingClass, document, {bindInto: 'thing'}));
+
+  return subdocs;
+}
+
+export function parseContentEntries(thingClass, value, {subdoc}) {
+  if (typeof value === 'string') {
+    return parseContentEntriesFromSourceText(thingClass, value, {subdoc});
+  } else if (Array.isArray(value)) {
+    return value.map(doc => subdoc(thingClass, doc, {bindInto: 'thing'}));
+  } else {
+    return value;
+  }
+}
+
+export function parseCommentary(value, {subdoc, CommentaryEntry}) {
+  return parseContentEntries(CommentaryEntry, value, {subdoc});
+}
+
+export function parseCreditingSources(value, {subdoc, CreditingSourcesEntry}) {
+  return parseContentEntries(CreditingSourcesEntry, value, {subdoc});
+}
+
+export function parseReferencingSources(value, {subdoc, ReferencingSourcesEntry}) {
+  return parseContentEntries(ReferencingSourcesEntry, value, {subdoc});
+}
+
+export function parseLyrics(value, {subdoc, LyricsEntry}) {
+  if (
+    typeof value === 'string' &&
+    !multipleLyricsDetectionRegex.test(value)
+  ) {
+    const document = {'Body': value};
+
+    return [subdoc(LyricsEntry, document, {bindInto: 'thing'})];
+  }
+
+  return parseContentEntries(LyricsEntry, value, {subdoc});
+}
+
 // documentModes: Symbols indicating sets of behavior for loading and processing
 // data files.
 export const documentModes = {
@@ -688,16 +1022,23 @@ export const documentModes = {
 export function getAllDataSteps() {
   try {
     thingConstructors;
-  } catch (error) {
+  } catch {
     throw new Error(`Thing constructors aren't ready yet, can't get all data steps`);
   }
 
   const steps = [];
 
+  const seenLoadingFns = new Set();
+
   for (const thingConstructor of Object.values(thingConstructors)) {
     const getSpecFn = thingConstructor[Thing.getYamlLoadingSpec];
     if (!getSpecFn) continue;
 
+    // Subclasses can expose literally the same static properties
+    // by inheritence. We don't want to double-count those!
+    if (seenLoadingFns.has(getSpecFn)) continue;
+    seenLoadingFns.add(getSpecFn);
+
     steps.push(getSpecFn({
       documentModes,
       thingConstructors,
@@ -890,7 +1231,7 @@ export function processThingsFromDataStep(documents, dataStep) {
         throw new Error(`Class "${thingClass.name}" doesn't specify Thing.yamlDocumentSpec`);
       }
 
-      fn = makeProcessDocument(thingClass, spec);
+      fn = makeProcessDocument(thingClass, {...spec, processDocument});
       submap.set(thingClass, fn);
     }
 
@@ -905,15 +1246,23 @@ export function processThingsFromDataStep(documents, dataStep) {
       const aggregate = openAggregate({message: `Errors processing documents`});
 
       documents.forEach(
-        decorateErrorWithIndex(document => {
+        decorateErrorWithIndex((document, index) => {
           const {thing, aggregate: subAggregate} =
             processDocument(document, dataStep.documentThing);
 
+          thing[Thing.yamlSourceDocument] = document;
+          thing[Thing.yamlSourceDocumentPlacement] =
+            [documentModes.allInOne, index];
+
           result.push(thing);
           aggregate.call(subAggregate.close);
         }));
 
-      return {aggregate, result};
+      return {
+        aggregate,
+        result,
+        things: result,
+      };
     }
 
     case documentModes.oneDocumentTotal: {
@@ -923,7 +1272,15 @@ export function processThingsFromDataStep(documents, dataStep) {
       const {thing, aggregate} =
         processDocument(documents[0], dataStep.documentThing);
 
-      return {aggregate, result: thing};
+      thing[Thing.yamlSourceDocument] = documents[0];
+      thing[Thing.yamlSourceDocumentPlacement] =
+        [documentModes.oneDocumentTotal];
+
+      return {
+        aggregate,
+        result: thing,
+        things: [thing],
+      };
     }
 
     case documentModes.headerAndEntries: {
@@ -938,6 +1295,10 @@ export function processThingsFromDataStep(documents, dataStep) {
       const {thing: headerThing, aggregate: headerAggregate} =
         processDocument(headerDocument, dataStep.headerDocumentThing);
 
+      headerThing[Thing.yamlSourceDocument] = headerDocument;
+      headerThing[Thing.yamlSourceDocumentPlacement] =
+        [documentModes.headerAndEntries, 'header'];
+
       try {
         headerAggregate.close();
       } catch (caughtError) {
@@ -951,6 +1312,10 @@ export function processThingsFromDataStep(documents, dataStep) {
         const {thing: entryThing, aggregate: entryAggregate} =
           processDocument(entryDocument, dataStep.entryDocumentThing);
 
+        entryThing[Thing.yamlSourceDocument] = entryDocument;
+        entryThing[Thing.yamlSourceDocumentPlacement] =
+          [documentModes.headerAndEntries, 'entry', index];
+
         entryThings.push(entryThing);
 
         try {
@@ -967,6 +1332,7 @@ export function processThingsFromDataStep(documents, dataStep) {
           header: headerThing,
           entries: entryThings,
         },
+        things: [headerThing, ...entryThings],
       };
     }
 
@@ -980,7 +1346,15 @@ export function processThingsFromDataStep(documents, dataStep) {
       const {thing, aggregate} =
         processDocument(documents[0], dataStep.documentThing);
 
-      return {aggregate, result: thing};
+      thing[Thing.yamlSourceDocument] = documents[0];
+      thing[Thing.yamlSourceDocumentPlacement] =
+        [documentModes.onePerFile];
+
+      return {
+        aggregate,
+        result: thing,
+        things: [thing],
+      };
     }
 
     default:
@@ -1080,9 +1454,16 @@ export async function processThingsFromDataSteps(documentLists, fileLists, dataS
           file: files,
           documents: documentLists,
         }).map(({file, documents}) => {
-            const {result, aggregate} =
+            const {result, aggregate, things} =
               processThingsFromDataStep(documents, dataStep);
 
+            for (const thing of things) {
+              thing[Thing.yamlSourceFilename] =
+                path.relative(dataPath, file)
+                  .split(path.sep)
+                  .join(path.posix.sep);
+            }
+
             const close = decorateErrorWithFileFromDataPath(aggregate.close, {dataPath});
             aggregate.close = () => close({file});
 
@@ -1225,93 +1606,107 @@ export async function loadAndProcessDataDocuments(dataSteps, {dataPath}) {
 // Data linking! Basically, provide (portions of) wikiData to the Things which
 // require it - they'll expose dynamically computed properties as a result (many
 // of which are required for page HTML generation and other expected behavior).
-export function linkWikiDataArrays(wikiData) {
+export function linkWikiDataArrays(wikiData, {bindFind, bindReverse}) {
   const linkWikiDataSpec = new Map([
-    [wikiData.albumData, [
-      'albumData',
-      'artTagData',
-      'artistData',
-      'groupData',
-      'trackData',
+    // entries must be present here even without any properties to explicitly
+    // link if the 'find' or 'reverse' properties will be implicitly linked
+
+    ['albumData', [
+      'artworkData',
       'wikiInfo',
     ]],
 
-    [wikiData.artTagData, [
-      'albumData',
-      'trackData',
-    ]],
+    ['artTagData', [/* reverse */]],
 
-    [wikiData.artistData, [
-      'albumData',
-      'artistData',
-      'flashData',
-      'groupData',
-      'trackData',
-    ]],
+    ['artistData', [/* find, reverse */]],
 
-    [wikiData.flashData, [
-      'artistData',
-      'flashActData',
-      'trackData',
+    ['artworkData', ['artworkData']],
+
+    ['commentaryData', [/* find */]],
+
+    ['creditingSourceData', [/* find */]],
+
+    ['flashData', [
       'wikiInfo',
     ]],
 
-    [wikiData.flashActData, [
-      'flashData',
-      'flashSideData',
-    ]],
+    ['flashActData', [/* find, reverse */]],
 
-    [wikiData.flashSideData, [
-      'flashActData',
-    ]],
+    ['flashSideData', [/* find */]],
 
-    [wikiData.groupData, [
-      'albumData',
-      'artistData',
-      'groupCategoryData',
-    ]],
+    ['groupData', [/* find, reverse */]],
 
-    [wikiData.groupCategoryData, [
-      'groupData',
-    ]],
+    ['groupCategoryData', [/* find */]],
 
-    [wikiData.homepageLayout?.rows, [
-      'albumData',
-      'groupData',
-    ]],
+    ['homepageLayout.sections.rows', [/* find */]],
+
+    ['lyricsData', [/* find */]],
 
-    [wikiData.trackData, [
-      'albumData',
-      'artTagData',
-      'artistData',
-      'flashData',
+    ['referencingSourceData', [/* find */]],
+
+    ['seriesData', [/* find */]],
+
+    ['trackData', [
+      'artworkData',
       'trackData',
-      'trackSectionData',
       'wikiInfo',
     ]],
 
-    [wikiData.trackSectionData, [
-      'albumData',
-    ]],
+    ['trackSectionData', [/* reverse */]],
 
-    [[wikiData.wikiInfo], [
-      'groupData',
-    ]],
+    ['wikiInfo', [/* find */]],
   ]);
 
-  for (const [things, keys] of linkWikiDataSpec.entries()) {
-    if (things === undefined) continue;
+  const constructorHasFindMap = new Map();
+  const constructorHasReverseMap = new Map();
+
+  const boundFind = bindFind(wikiData);
+  const boundReverse = bindReverse(wikiData);
+
+  for (const [thingDataProp, keys] of linkWikiDataSpec.entries()) {
+    const thingData = getNestedProp(wikiData, thingDataProp);
+    const things =
+      (Array.isArray(thingData)
+        ? thingData.flat(Infinity)
+        : [thingData]);
+
     for (const thing of things) {
       if (thing === undefined) continue;
+
+      let hasFind;
+      if (constructorHasFindMap.has(thing.constructor)) {
+        hasFind = constructorHasFindMap.get(thing.constructor);
+      } else {
+        hasFind = 'find' in thing;
+        constructorHasFindMap.set(thing.constructor, hasFind);
+      }
+
+      if (hasFind) {
+        thing.find = boundFind;
+      }
+
+      let hasReverse;
+      if (constructorHasReverseMap.has(thing.constructor)) {
+        hasReverse = constructorHasReverseMap.get(thing.constructor);
+      } else {
+        hasReverse = 'reverse' in thing;
+        constructorHasReverseMap.set(thing.constructor, hasReverse);
+      }
+
+      if (hasReverse) {
+        thing.reverse = boundReverse;
+      }
+
       for (const key of keys) {
         if (!(key in wikiData)) continue;
+
         thing[key] = wikiData[key];
       }
     }
   }
 }
 
-export function sortWikiDataArrays(dataSteps, wikiData) {
+export function sortWikiDataArrays(dataSteps, wikiData, {bindFind, bindReverse}) {
   for (const [key, value] of Object.entries(wikiData)) {
     if (!Array.isArray(value)) continue;
     wikiData[key] = value.slice();
@@ -1327,7 +1722,7 @@ export function sortWikiDataArrays(dataSteps, wikiData) {
   // slices instead of the original arrays) - this is so that the object
   // caching system understands that it's working with a new ordering.
   // We still need to actually provide those updated arrays over again!
-  linkWikiDataArrays(wikiData);
+  linkWikiDataArrays(wikiData, {bindFind, bindReverse});
 }
 
 // Utility function for loading all wiki data from the provided YAML data
@@ -1339,6 +1734,7 @@ export function sortWikiDataArrays(dataSteps, wikiData) {
 export async function quickLoadAllFromYAML(dataPath, {
   find,
   bindFind,
+  bindReverse,
   getAllFindSpecs,
 
   showAggregate: customShowAggregate = showAggregate,
@@ -1363,7 +1759,7 @@ export async function quickLoadAllFromYAML(dataPath, {
     }
   }
 
-  linkWikiDataArrays(wikiData);
+  linkWikiDataArrays(wikiData, {bindFind, bindReverse});
 
   try {
     reportDirectoryErrors(wikiData, {getAllFindSpecs});
@@ -1389,7 +1785,203 @@ export async function quickLoadAllFromYAML(dataPath, {
     logWarn`Content text errors found.`;
   }
 
-  sortWikiDataArrays(dataSteps, wikiData);
+  sortWikiDataArrays(dataSteps, wikiData, {bindFind, bindReverse});
 
   return wikiData;
 }
+
+export function cruddilyGetAllThings(wikiData) {
+  const allThings = [];
+
+  for (const v of Object.values(wikiData)) {
+    if (Array.isArray(v)) {
+      allThings.push(...v);
+    } else {
+      allThings.push(v);
+    }
+  }
+
+  return allThings;
+}
+
+export function getThingLayoutForFilename(filename, wikiData) {
+  const things =
+    cruddilyGetAllThings(wikiData)
+      .filter(thing =>
+        thing[Thing.yamlSourceFilename] === filename);
+
+  if (empty(things)) {
+    return null;
+  }
+
+  const allDocumentModes =
+    unique(things.map(thing =>
+      thing[Thing.yamlSourceDocumentPlacement][0]));
+
+  if (allDocumentModes.length > 1) {
+    throw new Error(`More than one document mode for documents from ${filename}`);
+  }
+
+  const documentMode = allDocumentModes[0];
+
+  switch (documentMode) {
+    case documentModes.allInOne: {
+      return {
+        documentMode,
+        things:
+          things.sort((a, b) =>
+            a[Thing.yamlSourceDocumentPlacement][1] -
+            b[Thing.yamlSourceDocumentPlacement][1]),
+      };
+    }
+
+    case documentModes.oneDocumentTotal:
+    case documentModes.onePerFile: {
+      if (things.length > 1) {
+        throw new Error(`More than one document for ${filename}`);
+      }
+
+      return {
+        documentMode,
+        thing: things[0],
+      };
+    }
+
+    case documentModes.headerAndEntries: {
+      const headerThings =
+        things.filter(thing =>
+          thing[Thing.yamlSourceDocumentPlacement][1] === 'header');
+
+      if (headerThings.length > 1) {
+        throw new Error(`More than one header document for ${filename}`);
+      }
+
+      return {
+        documentMode,
+        headerThing: headerThings[0] ?? null,
+        entryThings:
+          things
+            .filter(thing =>
+              thing[Thing.yamlSourceDocumentPlacement][1] === 'entry')
+            .sort((a, b) =>
+              a[Thing.yamlSourceDocumentPlacement][2] -
+              b[Thing.yamlSourceDocumentPlacement][2]),
+      };
+    }
+
+    default: {
+      return {documentMode};
+    }
+  }
+}
+
+export function flattenThingLayoutToDocumentOrder(layout) {
+  switch (layout.documentMode) {
+    case documentModes.oneDocumentTotal:
+    case documentModes.onePerFile: {
+      if (layout.thing) {
+        return [0];
+      } else {
+        return [];
+      }
+    }
+
+    case documentModes.allInOne: {
+      const indices =
+        layout.things
+          .map(thing => thing[Thing.yamlSourceDocumentPlacement][1]);
+
+      return indices;
+    }
+
+    case documentModes.headerAndEntries: {
+      const entryIndices =
+        layout.entryThings
+          .map(thing => thing[Thing.yamlSourceDocumentPlacement][2])
+          .map(index => index + 1);
+
+      if (layout.headerThing) {
+        return [0, ...entryIndices];
+      } else {
+        return entryIndices;
+      }
+    }
+
+    default: {
+      throw new Error(`Unknown document mode`);
+    }
+  }
+}
+
+export function* splitDocumentsInYAMLSourceText(sourceText) {
+  // Not multiline!
+  const dividerRegex = /(?:\r\n|\n|^)-{3,}(?:\r\n|\n|$)/g;
+
+  let previousDivider = '';
+
+  while (true) {
+    const {lastIndex} = dividerRegex;
+    const match = dividerRegex.exec(sourceText);
+    if (match) {
+      const nextDivider = match[0];
+
+      yield {
+        previousDivider,
+        nextDivider,
+        text: sourceText.slice(lastIndex, match.index),
+      };
+
+      previousDivider = nextDivider;
+    } else {
+      const nextDivider = '';
+      const lineBreak = previousDivider.match(/\r?\n/)?.[0] ?? '';
+
+      yield {
+        previousDivider,
+        nextDivider,
+        text: sourceText.slice(lastIndex).replace(/(?<!\n)$/, lineBreak),
+      };
+
+      return;
+    }
+  }
+}
+
+export function recombineDocumentsIntoYAMLSourceText(documents) {
+  const dividers =
+    unique(
+      documents
+        .flatMap(d => [d.previousDivider, d.nextDivider])
+        .filter(Boolean));
+
+  const divider = dividers[0];
+
+  if (dividers.length > 1) {
+    // TODO: Accommodate mixed dividers as best as we can lol
+    logWarn`Found multiple dividers in this file, using only ${divider}`;
+  }
+
+  let sourceText = '';
+
+  for (const document of documents) {
+    if (sourceText) {
+      sourceText += divider;
+    }
+
+    sourceText += document.text;
+  }
+
+  return sourceText;
+}
+
+export function reorderDocumentsInYAMLSourceText(sourceText, order) {
+  const sourceDocuments =
+    Array.from(splitDocumentsInYAMLSourceText(sourceText));
+
+  const sortedDocuments =
+    Array.from(
+      order,
+      sourceIndex => sourceDocuments[sourceIndex]);
+
+  return recombineDocumentsIntoYAMLSourceText(sortedDocuments);
+}