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hsmusic-wiki - HSMusic - static wiki software cataloguing collaborative creation
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-rw-r--r--src/data/cacheable-object.js18
-rw-r--r--src/data/checks.js3
-rw-r--r--src/data/composite.js175
-rw-r--r--src/data/composite/control-flow/exposeWhetherDependencyAvailable.js42
-rw-r--r--src/data/composite/control-flow/index.js1
-rw-r--r--src/data/composite/control-flow/withResultOfAvailabilityCheck.js1
-rw-r--r--src/data/composite/data/excludeFromList.js5
-rw-r--r--src/data/composite/data/fillMissingListItems.js5
-rw-r--r--src/data/composite/data/index.js29
-rw-r--r--src/data/composite/data/withFilteredList.js6
-rw-r--r--src/data/composite/data/withFlattenedList.js6
-rw-r--r--src/data/composite/data/withIndexInList.js38
-rw-r--r--src/data/composite/data/withMappedList.js6
-rw-r--r--src/data/composite/data/withNearbyItemFromList.js73
-rw-r--r--src/data/composite/data/withPropertiesFromList.js6
-rw-r--r--src/data/composite/data/withPropertyFromList.js6
-rw-r--r--src/data/composite/data/withPropertyFromObject.js28
-rw-r--r--src/data/composite/data/withSortedList.js6
-rw-r--r--src/data/composite/data/withSum.js33
-rw-r--r--src/data/composite/data/withUnflattenedList.js6
-rw-r--r--src/data/composite/things/album/index.js1
-rw-r--r--src/data/composite/things/album/withTrackSections.js21
-rw-r--r--src/data/composite/things/album/withTracks.js13
-rw-r--r--src/data/composite/things/artist/artistTotalDuration.js70
-rw-r--r--src/data/composite/things/artist/index.js1
-rw-r--r--src/data/composite/things/contribution/index.js7
-rw-r--r--src/data/composite/things/contribution/inheritFromContributionPresets.js61
-rw-r--r--src/data/composite/things/contribution/thingPropertyMatches.js33
-rw-r--r--src/data/composite/things/contribution/thingReferenceTypeMatches.js39
-rw-r--r--src/data/composite/things/contribution/withContainingReverseContributionList.js40
-rw-r--r--src/data/composite/things/contribution/withContributionArtist.js34
-rw-r--r--src/data/composite/things/contribution/withContributionContext.js45
-rw-r--r--src/data/composite/things/contribution/withMatchingContributionPresets.js70
-rw-r--r--src/data/composite/things/track/index.js4
-rw-r--r--src/data/composite/things/track/inheritContributionListFromOriginalRelease.js44
-rw-r--r--src/data/composite/things/track/withContainingTrackSection.js1
-rw-r--r--src/data/composite/things/track/withDate.js34
-rw-r--r--src/data/composite/things/track/withHasUniqueCoverArt.js5
-rw-r--r--src/data/composite/things/track/withTrackArtDate.js80
-rw-r--r--src/data/composite/wiki-data/exitWithoutContribs.js1
-rw-r--r--src/data/composite/wiki-data/index.js5
-rw-r--r--src/data/composite/wiki-data/withClonedThings.js68
-rw-r--r--src/data/composite/wiki-data/withContributionListSums.js95
-rw-r--r--src/data/composite/wiki-data/withCoverArtDate.js70
-rw-r--r--src/data/composite/wiki-data/withRecontextualizedContributionList.js101
-rw-r--r--src/data/composite/wiki-data/withRedatedContributionList.js127
-rw-r--r--src/data/composite/wiki-data/withResolvedContribs.js115
-rw-r--r--src/data/composite/wiki-data/withReverseContributionList.js120
-rw-r--r--src/data/composite/wiki-data/withReverseReferenceList.js111
-rw-r--r--src/data/composite/wiki-properties/contributionList.js31
-rw-r--r--src/data/composite/wiki-properties/index.js1
-rw-r--r--src/data/composite/wiki-properties/thing.js31
-rw-r--r--src/data/things/album.js78
-rw-r--r--src/data/things/artist.js125
-rw-r--r--src/data/things/contribution.js265
-rw-r--r--src/data/things/flash.js27
-rw-r--r--src/data/things/index.js2
-rw-r--r--src/data/things/language.js237
-rw-r--r--src/data/things/track.js123
-rw-r--r--src/data/things/wiki-info.js42
-rw-r--r--src/data/validators.js55
-rw-r--r--src/data/yaml.js133
62 files changed, 2698 insertions, 361 deletions
diff --git a/src/data/cacheable-object.js b/src/data/cacheable-object.js
index 4a89b774..010d967a 100644
--- a/src/data/cacheable-object.js
+++ b/src/data/cacheable-object.js
@@ -132,7 +132,11 @@ export default class CacheableObject {
         return;
       }
 
-      if ('default' in update) {
+      if (
+        typeof update === 'object' &&
+        update !== null &&
+        'default' in update
+      ) {
         this[property] = update?.default;
       } else {
         this[property] = null;
@@ -370,6 +374,18 @@ export default class CacheableObject {
 
     return object.#propertyUpdateValues[key] ?? null;
   }
+
+  static clone(object) {
+    const newObject = Reflect.construct(object.constructor, []);
+
+    this.copyUpdateValuesOnto(object, newObject);
+
+    return newObject;
+  }
+
+  static copyUpdateValuesOnto(source, target) {
+    Object.assign(target, source.#propertyUpdateValues);
+  }
 }
 
 export class CacheableObjectPropertyValueError extends Error {
diff --git a/src/data/checks.js b/src/data/checks.js
index f3741a19..ad621bab 100644
--- a/src/data/checks.js
+++ b/src/data/checks.js
@@ -95,6 +95,7 @@ export function reportDirectoryErrors(wikiData, {
   const seenDuplicateSets = new Map();
   const deduplicateDuplicateSets = [];
 
+  iterateSets:
   for (const set of duplicateSets) {
     if (seenDuplicateSets.has(set.directory)) {
       const placeLists = seenDuplicateSets.get(set.directory);
@@ -106,7 +107,7 @@ export function reportDirectoryErrors(wikiData, {
         // Two artists named Foodog aren't going to match two tracks named
         // Foodog.
         if (compareArrays(places, set.places, {checkOrder: false})) {
-          continue;
+          continue iterateSets;
         }
       }
 
diff --git a/src/data/composite.js b/src/data/composite.js
index 33d69a68..ea7a3480 100644
--- a/src/data/composite.js
+++ b/src/data/composite.js
@@ -758,6 +758,9 @@ export function compositeFrom(description) {
     anyStepsUseUpdateValue ||
     anyStepsUpdate;
 
+  const stepsFirstTimeCalling =
+    Array.from({length: steps.length}).fill(true);
+
   const stepEntries = stitchArrays({
     step: steps,
     stepComposes: stepsCompose,
@@ -977,8 +980,16 @@ export function compositeFrom(description) {
           (expectingTransform
             ? {[input.updateValue()]: valueSoFar}
             : {}),
-        [input.myself()]: initialDependencies?.['this'] ?? null,
-        [input.thisProperty()]: initialDependencies?.['thisProperty'] ?? null,
+
+        [input.myself()]:
+          (initialDependencies && Object.hasOwn(initialDependencies, 'this')
+            ? initialDependencies.this
+            : null),
+
+        [input.thisProperty()]:
+          (initialDependencies && Object.hasOwn(initialDependencies, 'thisProperty')
+            ? initialDependencies.thisProperty
+            : null),
       };
 
       const selectDependencies =
@@ -1028,7 +1039,123 @@ export function compositeFrom(description) {
       const naturalEvaluate = () => {
         const [name, ...argsLayout] = getExpectedEvaluation();
 
-        let args;
+        let args = argsLayout;
+
+        let effectiveDependencies;
+        let reviewAccessedDependencies;
+
+        if (stepsFirstTimeCalling[i]) {
+          const expressedDependencies =
+            selectDependencies;
+
+          const remainingDependencies =
+            new Set(expressedDependencies);
+
+          const unavailableDependencies = [];
+          const accessedDependencies = [];
+
+          effectiveDependencies =
+            new Proxy(filteredDependencies, {
+              get(target, key) {
+                accessedDependencies.push(key);
+                remainingDependencies.delete(key);
+
+                const value = target[key];
+
+                if (value === undefined) {
+                  unavailableDependencies.push(key);
+                }
+
+                return value;
+              },
+            });
+
+          reviewAccessedDependencies = () => {
+            const topAggregate =
+              openAggregate({
+                message: `Errors in accessed dependencies`,
+              });
+
+            const showDependency = dependency =>
+              (isInputToken(dependency)
+                ? getInputTokenShape(dependency) +
+                  `(` +
+                  inspect(getInputTokenValue(dependency), {compact: true}) +
+                  ')'
+                : dependency.toString());
+
+            let anyErrors = false;
+
+            for (const dependency of remainingDependencies) {
+              topAggregate.push(new Error(
+                `Expected to access ${showDependency(dependency)}`));
+
+              anyErrors = true;
+            }
+
+            for (const dependency of unavailableDependencies) {
+              const subAggregate =
+                openAggregate({
+                  message:
+                    `Accessed ${showDependency(dependency)}, which is unavailable`,
+                });
+
+              let reason = false;
+
+              if (!expressedDependencies.includes(dependency)) {
+                subAggregate.push(new Error(
+                  `Missing from step's expressed dependencies`));
+                reason = true;
+              }
+
+              if (filterableDependencies[dependency] === undefined) {
+                subAggregate.push(
+                  new Error(
+                    `Not available` +
+                    (isInputToken(dependency)
+                      ? ` in input()-type dependencies`
+                   : dependency.startsWith('#')
+                      ? ` in local dependencies`
+                      : ` on object dependencies`)));
+                reason = true;
+              }
+
+              if (!reason) {
+                subAggregate.push(new Error(
+                  `Not sure why this is unavailable, sorry!`));
+              }
+
+              topAggregate.call(subAggregate.close);
+
+              anyErrors = true;
+            }
+
+            if (anyErrors) {
+              topAggregate.push(new Error(
+                `These dependencies, in total, were accessed:` +
+                (empty(accessedDependencies)
+                  ? ` (none)`
+               : accessedDependencies.length === 1
+                  ? showDependency(accessedDependencies[0])
+                  : `\n` +
+                    accessedDependencies
+                      .map(showDependency)
+                      .map(line => `  - ${line}`)
+                      .join('\n'))));
+            }
+
+            topAggregate.close();
+          };
+        } else {
+          effectiveDependencies = filteredDependencies;
+          reviewAccessedDependencies = null;
+        }
+
+        args =
+          args.map(arg =>
+            (arg === filteredDependencies
+              ? effectiveDependencies
+              : arg));
 
         if (stepComposes) {
           let continuation;
@@ -1037,17 +1164,50 @@ export function compositeFrom(description) {
             _prepareContinuation(callingTransformForThisStep));
 
           args =
-            argsLayout.map(arg =>
+            args.map(arg =>
               (arg === continuationSymbol
                 ? continuation
                 : arg));
         } else {
           args =
-            argsLayout.filter(arg => arg !== continuationSymbol);
+            args.filter(arg => arg !== continuationSymbol);
         }
 
-        return expose[name](...args);
-      }
+        let stepError;
+        try {
+          return expose[name](...args);
+        } catch (error) {
+          stepError = error;
+        } finally {
+          stepsFirstTimeCalling[i] = false;
+
+          let reviewError;
+          if (reviewAccessedDependencies) {
+            try {
+              reviewAccessedDependencies();
+            } catch (error) {
+              reviewError = error;
+            }
+          }
+
+          const stepPart =
+            `step ${i+1}` +
+            (isBase
+              ? ` (base)`
+              : ` of ${steps.length}`) +
+            (step.annotation ? `, ${step.annotation}` : ``);
+
+          if (stepError && reviewError) {
+            throw new AggregateError(
+              [stepError, reviewError],
+              `Errors in ${stepPart}`);
+          } else if (stepError || reviewError) {
+            throw new Error(
+              `Error in ${stepPart}`,
+              {cause: stepError || reviewError});
+          }
+        }
+      };
 
       switch (step.cache) {
         // Warning! Highly WIP!
@@ -1223,6 +1383,7 @@ export function compositeFrom(description) {
           `Error computing composition` +
           (annotation ? ` ${annotation}` : ''));
         error.cause = thrownError;
+        error[Symbol.for('hsmusic.aggregate.translucent')] = true;
         throw error;
       }
     };
diff --git a/src/data/composite/control-flow/exposeWhetherDependencyAvailable.js b/src/data/composite/control-flow/exposeWhetherDependencyAvailable.js
new file mode 100644
index 00000000..a2fdd6b0
--- /dev/null
+++ b/src/data/composite/control-flow/exposeWhetherDependencyAvailable.js
@@ -0,0 +1,42 @@
+// Exposes true if a dependency is available, and false otherwise,
+// or the reverse if the `negate` input is set true.
+//
+// See withResultOfAvailabilityCheck for {mode} options.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import inputAvailabilityCheckMode from './inputAvailabilityCheckMode.js';
+import withResultOfAvailabilityCheck from './withResultOfAvailabilityCheck.js';
+
+export default templateCompositeFrom({
+  annotation: `exposeWhetherDependencyAvailable`,
+
+  compose: false,
+
+  inputs: {
+    dependency: input({acceptsNull: true}),
+
+    mode: inputAvailabilityCheckMode(),
+
+    negate: input({type: 'boolean', defaultValue: false}),
+  },
+
+  steps: () => [
+    withResultOfAvailabilityCheck({
+      from: input('dependency'),
+      mode: input('mode'),
+    }),
+
+    {
+      dependencies: ['#availability', input('negate')],
+
+      compute: ({
+        ['#availability']: availability,
+        [input('negate')]: negate,
+      }) =>
+        (negate
+          ? !availability
+          : availability),
+    },
+  ],
+});
diff --git a/src/data/composite/control-flow/index.js b/src/data/composite/control-flow/index.js
index 7fad88b2..6148d465 100644
--- a/src/data/composite/control-flow/index.js
+++ b/src/data/composite/control-flow/index.js
@@ -9,6 +9,7 @@ export {default as exposeConstant} from './exposeConstant.js';
 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 raiseOutputWithoutDependency} from './raiseOutputWithoutDependency.js';
 export {default as raiseOutputWithoutUpdateValue} from './raiseOutputWithoutUpdateValue.js';
 export {default as withResultOfAvailabilityCheck} from './withResultOfAvailabilityCheck.js';
diff --git a/src/data/composite/control-flow/withResultOfAvailabilityCheck.js b/src/data/composite/control-flow/withResultOfAvailabilityCheck.js
index a6942014..1d90b324 100644
--- a/src/data/composite/control-flow/withResultOfAvailabilityCheck.js
+++ b/src/data/composite/control-flow/withResultOfAvailabilityCheck.js
@@ -17,6 +17,7 @@
 //  - exitWithoutUpdateValue
 //  - exposeDependencyOrContinue
 //  - exposeUpdateValueOrContinue
+//  - exposeWhetherDependencyAvailable
 //  - raiseOutputWithoutDependency
 //  - raiseOutputWithoutUpdateValue
 //
diff --git a/src/data/composite/data/excludeFromList.js b/src/data/composite/data/excludeFromList.js
index d798dcdc..2a3e818e 100644
--- a/src/data/composite/data/excludeFromList.js
+++ b/src/data/composite/data/excludeFromList.js
@@ -5,11 +5,6 @@
 // See also:
 //  - fillMissingListItems
 //
-// More list utilities:
-//  - withFilteredList, withMappedList, withSortedList
-//  - withFlattenedList, withUnflattenedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 import {empty} from '#sugar';
diff --git a/src/data/composite/data/fillMissingListItems.js b/src/data/composite/data/fillMissingListItems.js
index 4f818a79..356b1119 100644
--- a/src/data/composite/data/fillMissingListItems.js
+++ b/src/data/composite/data/fillMissingListItems.js
@@ -4,11 +4,6 @@
 // See also:
 //  - excludeFromList
 //
-// More list utilities:
-//  - withFilteredList, withMappedList, withSortedList
-//  - withFlattenedList, withUnflattenedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 
diff --git a/src/data/composite/data/index.js b/src/data/composite/data/index.js
index 256c0490..c80bb350 100644
--- a/src/data/composite/data/index.js
+++ b/src/data/composite/data/index.js
@@ -3,15 +3,32 @@
 // Entries here may depend on entries in #composite/control-flow.
 //
 
+// Utilities which act on generic objects
+
+export {default as withPropertiesFromObject} from './withPropertiesFromObject.js';
+export {default as withPropertyFromObject} from './withPropertyFromObject.js';
+
+// Utilities which act on generic lists
+
 export {default as excludeFromList} from './excludeFromList.js';
+
 export {default as fillMissingListItems} from './fillMissingListItems.js';
+export {default as withUniqueItemsOnly} from './withUniqueItemsOnly.js';
+
 export {default as withFilteredList} from './withFilteredList.js';
-export {default as withFlattenedList} from './withFlattenedList.js';
 export {default as withMappedList} from './withMappedList.js';
-export {default as withPropertiesFromList} from './withPropertiesFromList.js';
-export {default as withPropertiesFromObject} from './withPropertiesFromObject.js';
-export {default as withPropertyFromList} from './withPropertyFromList.js';
-export {default as withPropertyFromObject} from './withPropertyFromObject.js';
 export {default as withSortedList} from './withSortedList.js';
+
+export {default as withPropertyFromList} from './withPropertyFromList.js';
+export {default as withPropertiesFromList} from './withPropertiesFromList.js';
+
+export {default as withFlattenedList} from './withFlattenedList.js';
 export {default as withUnflattenedList} from './withUnflattenedList.js';
-export {default as withUniqueItemsOnly} from './withUniqueItemsOnly.js';
+
+export {default as withIndexInList} from './withIndexInList.js';
+export {default as withNearbyItemFromList} from './withNearbyItemFromList.js';
+
+// Utilities which act on slightly more particular data forms
+// (probably, containers of particular kinds of values)
+
+export {default as withSum} from './withSum.js';
diff --git a/src/data/composite/data/withFilteredList.js b/src/data/composite/data/withFilteredList.js
index 82e56903..60fe66f4 100644
--- a/src/data/composite/data/withFilteredList.js
+++ b/src/data/composite/data/withFilteredList.js
@@ -16,12 +16,6 @@
 //  - withMappedList
 //  - withSortedList
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFlattenedList, withUnflattenedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 
diff --git a/src/data/composite/data/withFlattenedList.js b/src/data/composite/data/withFlattenedList.js
index edfa3403..31b1a742 100644
--- a/src/data/composite/data/withFlattenedList.js
+++ b/src/data/composite/data/withFlattenedList.js
@@ -5,12 +5,6 @@
 // See also:
 //  - withUnflattenedList
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFilteredList, withMappedList, withSortedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 
diff --git a/src/data/composite/data/withIndexInList.js b/src/data/composite/data/withIndexInList.js
new file mode 100644
index 00000000..b1af2033
--- /dev/null
+++ b/src/data/composite/data/withIndexInList.js
@@ -0,0 +1,38 @@
+// Gets the index of the provided item in the provided list. Note that this
+// will output -1 if the item is not found, and this may be detected using
+// any availability check with type: 'index'. If the list includes the item
+// twice, the output index will be of the first match.
+//
+// Both the list and item must be provided.
+//
+// See also:
+//  - withNearbyItemFromList
+//  - exitWithoutDependency
+//  - raiseOutputWithoutDependency
+//
+
+import {input, templateCompositeFrom} from '#composite';
+
+export default templateCompositeFrom({
+  annotation: `withIndexInList`,
+
+  inputs: {
+    list: input({acceptsNull: false, type: 'array'}),
+    item: input({acceptsNull: false}),
+  },
+
+  outputs: ['#index'],
+
+  steps: () => [
+    {
+      dependencies: [input('list'), input('item')],
+      compute: (continuation, {
+        [input('list')]: list,
+        [input('item')]: item,
+      }) => continuation({
+        ['#index']:
+          list.indexOf(item),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/data/withMappedList.js b/src/data/composite/data/withMappedList.js
index e0a700b2..0bc63a92 100644
--- a/src/data/composite/data/withMappedList.js
+++ b/src/data/composite/data/withMappedList.js
@@ -5,12 +5,6 @@
 //  - withFilteredList
 //  - withSortedList
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFlattenedList, withUnflattenedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 
diff --git a/src/data/composite/data/withNearbyItemFromList.js b/src/data/composite/data/withNearbyItemFromList.js
new file mode 100644
index 00000000..83a8cc21
--- /dev/null
+++ b/src/data/composite/data/withNearbyItemFromList.js
@@ -0,0 +1,73 @@
+// Gets a nearby (typically adjacent) item in a list, meaning the item which is
+// placed at a particular offset compared to the provided item. This is null if
+// the provided list doesn't include the provided item at all, and also if the
+// offset would read past either end of the list - except if configured:
+//
+//  - If the 'wrap' input is provided (as true), the offset will loop around
+//    and continue from the opposing end.
+//
+//  - If the 'valuePastEdge' input is provided, that value will be output
+//    instead of null.
+//
+// Both the list and item must be provided.
+//
+// See also:
+//  - withIndexInList
+//
+
+import {input, templateCompositeFrom} from '#composite';
+import {atOffset} from '#sugar';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+import withIndexInList from './withIndexInList.js';
+
+export default templateCompositeFrom({
+  annotation: `withNearbyItemFromList`,
+
+  inputs: {
+    list: input({acceptsNull: false, type: 'array'}),
+    item: input({acceptsNull: false}),
+
+    offset: input({type: 'number'}),
+    wrap: input({type: 'boolean', defaultValue: false}),
+  },
+
+  outputs: ['#nearbyItem'],
+
+  steps: () => [
+    withIndexInList({
+      list: input('list'),
+      item: input('item'),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#index',
+      mode: input.value('index'),
+
+      output: input.value({
+        ['#nearbyItem']:
+          null,
+      }),
+    }),
+
+    {
+      dependencies: [
+        input('list'),
+        input('offset'),
+        input('wrap'),
+        '#index',
+      ],
+
+      compute: (continuation, {
+        [input('list')]: list,
+        [input('offset')]: offset,
+        [input('wrap')]: wrap,
+        ['#index']: index,
+      }) => continuation({
+        ['#nearbyItem']:
+          atOffset(list, index, offset, {wrap}),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/data/withPropertiesFromList.js b/src/data/composite/data/withPropertiesFromList.js
index 08907bab..fb4134bc 100644
--- a/src/data/composite/data/withPropertiesFromList.js
+++ b/src/data/composite/data/withPropertiesFromList.js
@@ -8,12 +8,6 @@
 //  - withPropertiesFromObject
 //  - withPropertyFromList
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFilteredList, withMappedList, withSortedList
-//  - withFlattenedList, withUnflattenedList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 import {isString, validateArrayItems} from '#validators';
diff --git a/src/data/composite/data/withPropertyFromList.js b/src/data/composite/data/withPropertyFromList.js
index a2c66d77..65ebf77b 100644
--- a/src/data/composite/data/withPropertyFromList.js
+++ b/src/data/composite/data/withPropertyFromList.js
@@ -9,12 +9,6 @@
 //  - withPropertiesFromList
 //  - withPropertyFromObject
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFilteredList, withMappedList, withSortedList
-//  - withFlattenedList, withUnflattenedList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 
diff --git a/src/data/composite/data/withPropertyFromObject.js b/src/data/composite/data/withPropertyFromObject.js
index b31bab15..4f240506 100644
--- a/src/data/composite/data/withPropertyFromObject.js
+++ b/src/data/composite/data/withPropertyFromObject.js
@@ -2,11 +2,15 @@
 // If the object itself is null, or the object doesn't have the listed property,
 // the provided dependency will also be null.
 //
+// If the `internal` input is true, this reads the CacheableObject update value
+// of the object rather than its exposed value.
+//
 // See also:
 //  - withPropertiesFromObject
 //  - withPropertyFromList
 //
 
+import CacheableObject from '#cacheable-object';
 import {input, templateCompositeFrom} from '#composite';
 
 export default templateCompositeFrom({
@@ -15,6 +19,7 @@ export default templateCompositeFrom({
   inputs: {
     object: input({type: 'object', acceptsNull: true}),
     property: input({type: 'string'}),
+    internal: input({type: 'boolean', defaultValue: false}),
   },
 
   outputs: ({
@@ -49,20 +54,35 @@ export default templateCompositeFrom({
 
     {
       dependencies: [
-        '#output',
         input('object'),
         input('property'),
+        input('internal'),
       ],
 
       compute: (continuation, {
-        ['#output']: output,
         [input('object')]: object,
         [input('property')]: property,
+        [input('internal')]: internal,
       }) => continuation({
-        [output]:
+        '#value':
           (object === null
             ? null
-            : object[property] ?? null),
+         : internal
+            ? CacheableObject.getUpdateValue(object, property)
+                ?? null
+            : object[property]
+                ?? null),
+      }),
+    },
+
+    {
+      dependencies: ['#output', '#value'],
+
+      compute: (continuation, {
+        ['#output']: output,
+        ['#value']: value,
+      }) => continuation({
+        [output]: value,
       }),
     },
   ],
diff --git a/src/data/composite/data/withSortedList.js b/src/data/composite/data/withSortedList.js
index dd810786..a7d21768 100644
--- a/src/data/composite/data/withSortedList.js
+++ b/src/data/composite/data/withSortedList.js
@@ -27,12 +27,6 @@
 //  - withFilteredList
 //  - withMappedList
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFlattenedList, withUnflattenedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 
diff --git a/src/data/composite/data/withSum.js b/src/data/composite/data/withSum.js
new file mode 100644
index 00000000..484e9906
--- /dev/null
+++ b/src/data/composite/data/withSum.js
@@ -0,0 +1,33 @@
+// Gets the numeric total of adding all the values in a list together.
+// Values that are false, null, or undefined are skipped over.
+
+import {input, templateCompositeFrom} from '#composite';
+import {isNumber, sparseArrayOf} from '#validators';
+
+export default templateCompositeFrom({
+  annotation: `withSum`,
+
+  inputs: {
+    values: input({
+      validate: sparseArrayOf(isNumber),
+    }),
+  },
+
+  outputs: ['#sum'],
+
+  steps: () => [
+    {
+      dependencies: [input('values')],
+      compute: (continuation, {
+        [input('values')]: values,
+      }) => continuation({
+        ['#sum']:
+          values
+            .filter(item => typeof item === 'number')
+            .reduce(
+              (accumulator, value) => accumulator + value,
+              0),
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/data/withUnflattenedList.js b/src/data/composite/data/withUnflattenedList.js
index 39a666dc..820d628a 100644
--- a/src/data/composite/data/withUnflattenedList.js
+++ b/src/data/composite/data/withUnflattenedList.js
@@ -7,12 +7,6 @@
 // See also:
 //  - withFlattenedList
 //
-// More list utilities:
-//  - excludeFromList
-//  - fillMissingListItems
-//  - withFilteredList, withMappedList, withSortedList
-//  - withPropertyFromList, withPropertiesFromList
-//
 
 import {input, templateCompositeFrom} from '#composite';
 import {isWholeNumber, validateArrayItems} from '#validators';
diff --git a/src/data/composite/things/album/index.js b/src/data/composite/things/album/index.js
index 8b5098f0..0ef91b87 100644
--- a/src/data/composite/things/album/index.js
+++ b/src/data/composite/things/album/index.js
@@ -1 +1,2 @@
+export {default as withTrackSections} from './withTrackSections.js';
 export {default as withTracks} from './withTracks.js';
diff --git a/src/data/composite/things/album/withTrackSections.js b/src/data/composite/things/album/withTrackSections.js
new file mode 100644
index 00000000..a56bda31
--- /dev/null
+++ b/src/data/composite/things/album/withTrackSections.js
@@ -0,0 +1,21 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import find from '#find';
+
+import {withResolvedReferenceList} from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `withTrackSections`,
+
+  outputs: ['#trackSections'],
+
+  steps: () => [
+    withResolvedReferenceList({
+      list: 'trackSections',
+      data: 'ownTrackSectionData',
+      find: input.value(find.unqualifiedTrackSection),
+    }).outputs({
+      ['#resolvedReferenceList']: '#trackSections',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/album/withTracks.js b/src/data/composite/things/album/withTracks.js
index 3fe6dd2e..c8d27c4c 100644
--- a/src/data/composite/things/album/withTracks.js
+++ b/src/data/composite/things/album/withTracks.js
@@ -1,24 +1,17 @@
 import {input, templateCompositeFrom} from '#composite';
 
-import find from '#find';
-
-import {exitWithoutDependency} from '#composite/control-flow';
 import {withFlattenedList, withPropertyFromList} from '#composite/data';
 import {withResolvedReferenceList} from '#composite/wiki-data';
 
+import withTrackSections from './withTrackSections.js';
+
 export default templateCompositeFrom({
   annotation: `withTracks`,
 
   outputs: ['#tracks'],
 
   steps: () => [
-    withResolvedReferenceList({
-      list: 'trackSections',
-      data: 'ownTrackSectionData',
-      find: input.value(find.unqualifiedTrackSection),
-    }).outputs({
-      ['#resolvedReferenceList']: '#trackSections',
-    }),
+    withTrackSections(),
 
     withPropertyFromList({
       list: '#trackSections',
diff --git a/src/data/composite/things/artist/artistTotalDuration.js b/src/data/composite/things/artist/artistTotalDuration.js
new file mode 100644
index 00000000..ff709f28
--- /dev/null
+++ b/src/data/composite/things/artist/artistTotalDuration.js
@@ -0,0 +1,70 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {exposeDependency} from '#composite/control-flow';
+import {withFilteredList, withPropertyFromList} from '#composite/data';
+import {withContributionListSums, withReverseContributionList}
+  from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `artistTotalDuration`,
+
+  compose: false,
+
+  steps: () => [
+    withReverseContributionList({
+      data: 'trackData',
+      list: input.value('artistContribs'),
+    }).outputs({
+      '#reverseContributionList': '#contributionsAsArtist',
+    }),
+
+    withReverseContributionList({
+      data: 'trackData',
+      list: input.value('contributorContribs'),
+    }).outputs({
+      '#reverseContributionList': '#contributionsAsContributor',
+    }),
+
+    {
+      dependencies: [
+        '#contributionsAsArtist',
+        '#contributionsAsContributor',
+      ],
+
+      compute: (continuation, {
+        ['#contributionsAsArtist']: artistContribs,
+        ['#contributionsAsContributor']: contributorContribs,
+      }) => continuation({
+        ['#allContributions']: [
+          ...artistContribs,
+          ...contributorContribs,
+        ],
+      }),
+    },
+
+    withPropertyFromList({
+      list: '#allContributions',
+      property: input.value('thing'),
+    }),
+
+    withPropertyFromList({
+      list: '#allContributions.thing',
+      property: input.value('isOriginalRelease'),
+    }),
+
+    withFilteredList({
+      list: '#allContributions',
+      filter: '#allContributions.thing.isOriginalRelease',
+    }).outputs({
+      '#filteredList': '#originalContributions',
+    }),
+
+    withContributionListSums({
+      list: '#originalContributions',
+    }),
+
+    exposeDependency({
+      dependency: '#contributionListDuration',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/artist/index.js b/src/data/composite/things/artist/index.js
new file mode 100644
index 00000000..55514c71
--- /dev/null
+++ b/src/data/composite/things/artist/index.js
@@ -0,0 +1 @@
+export {default as artistTotalDuration} from './artistTotalDuration.js';
diff --git a/src/data/composite/things/contribution/index.js b/src/data/composite/things/contribution/index.js
new file mode 100644
index 00000000..9b22be2e
--- /dev/null
+++ b/src/data/composite/things/contribution/index.js
@@ -0,0 +1,7 @@
+export {default as inheritFromContributionPresets} from './inheritFromContributionPresets.js';
+export {default as thingPropertyMatches} from './thingPropertyMatches.js';
+export {default as thingReferenceTypeMatches} from './thingReferenceTypeMatches.js';
+export {default as withContainingReverseContributionList} from './withContainingReverseContributionList.js';
+export {default as withContributionArtist} from './withContributionArtist.js';
+export {default as withContributionContext} from './withContributionContext.js';
+export {default as withMatchingContributionPresets} from './withMatchingContributionPresets.js';
diff --git a/src/data/composite/things/contribution/inheritFromContributionPresets.js b/src/data/composite/things/contribution/inheritFromContributionPresets.js
new file mode 100644
index 00000000..82425b9c
--- /dev/null
+++ b/src/data/composite/things/contribution/inheritFromContributionPresets.js
@@ -0,0 +1,61 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromList, withPropertyFromObject} from '#composite/data';
+
+import withMatchingContributionPresets
+  from './withMatchingContributionPresets.js';
+
+export default templateCompositeFrom({
+  annotation: `inheritFromContributionPresets`,
+
+  inputs: {
+    property: input({type: 'string'}),
+  },
+
+  steps: () => [
+    withMatchingContributionPresets().outputs({
+      '#matchingContributionPresets': '#presets',
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#presets',
+      mode: input.value('empty'),
+    }),
+
+    withPropertyFromList({
+      list: '#presets',
+      property: input('property'),
+    }),
+
+    {
+      dependencies: ['#values'],
+
+      compute: (continuation, {
+        ['#values']: values,
+      }) => continuation({
+        ['#index']:
+          values.findIndex(value =>
+            value !== undefined &&
+            value !== null),
+      }),
+    },
+
+    raiseOutputWithoutDependency({
+      dependency: '#index',
+      mode: input.value('index'),
+    }),
+
+    {
+      dependencies: ['#values', '#index'],
+
+      compute: (continuation, {
+        ['#values']: values,
+        ['#index']: index,
+      }) => continuation({
+        ['#value']:
+          values[index],
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/contribution/thingPropertyMatches.js b/src/data/composite/things/contribution/thingPropertyMatches.js
new file mode 100644
index 00000000..4a37f2cf
--- /dev/null
+++ b/src/data/composite/things/contribution/thingPropertyMatches.js
@@ -0,0 +1,33 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {exitWithoutDependency} from '#composite/control-flow';
+
+export default templateCompositeFrom({
+  annotation: `thingPropertyMatches`,
+
+  compose: false,
+
+  inputs: {
+    value: input({type: 'string'}),
+  },
+
+  steps: () => [
+    exitWithoutDependency({
+      dependency: 'thingProperty',
+      value: input.value(false),
+    }),
+
+    {
+      dependencies: [
+        'thingProperty',
+        input('value'),
+      ],
+
+      compute: ({
+        ['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
new file mode 100644
index 00000000..2ee811af
--- /dev/null
+++ b/src/data/composite/things/contribution/thingReferenceTypeMatches.js
@@ -0,0 +1,39 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {exitWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: `thingReferenceTypeMatches`,
+
+  compose: false,
+
+  inputs: {
+    value: input({type: 'string'}),
+  },
+
+  steps: () => [
+    exitWithoutDependency({
+      dependency: 'thing',
+      value: input.value(false),
+    }),
+
+    withPropertyFromObject({
+      object: 'thing',
+      property: input.value('constructor'),
+    }),
+
+    {
+      dependencies: [
+        '#thing.constructor',
+        input('value'),
+      ],
+
+      compute: ({
+        ['#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
new file mode 100644
index 00000000..56704c8b
--- /dev/null
+++ b/src/data/composite/things/contribution/withContainingReverseContributionList.js
@@ -0,0 +1,40 @@
+// Get the artist's contribution list containing this property.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+import withContributionArtist from './withContributionArtist.js';
+
+export default templateCompositeFrom({
+  annotation: `withContainingReverseContributionList`,
+
+  inputs: {
+    artistProperty: input({
+      defaultDependency: 'artistProperty',
+      acceptsNull: true,
+    }),
+  },
+
+  outputs: ['#containingReverseContributionList'],
+
+  steps: () => [
+    raiseOutputWithoutDependency({
+      dependency: input('artistProperty'),
+      output: input.value({
+        ['#containingReverseContributionList']:
+          null,
+      }),
+    }),
+
+    withContributionArtist(),
+
+    withPropertyFromObject({
+      object: '#artist',
+      property: input('artistProperty'),
+    }).outputs({
+      ['#value']: '#containingReverseContributionList',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/contribution/withContributionArtist.js b/src/data/composite/things/contribution/withContributionArtist.js
new file mode 100644
index 00000000..5a611c1a
--- /dev/null
+++ b/src/data/composite/things/contribution/withContributionArtist.js
@@ -0,0 +1,34 @@
+import {input, templateCompositeFrom} from '#composite';
+import find from '#find';
+
+import {withPropertyFromObject} from '#composite/data';
+import {withResolvedReference} from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `withContributionArtist`,
+
+  inputs: {
+    ref: input({
+      type: 'string',
+      defaultDependency: 'artist',
+    }),
+  },
+
+  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),
+    }).outputs({
+      '#resolvedReference': '#artist',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/contribution/withContributionContext.js b/src/data/composite/things/contribution/withContributionContext.js
new file mode 100644
index 00000000..3c1c31c0
--- /dev/null
+++ b/src/data/composite/things/contribution/withContributionContext.js
@@ -0,0 +1,45 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+export default templateCompositeFrom({
+  annotation: `withContributionContext`,
+
+  outputs: [
+    '#contributionTarget',
+    '#contributionProperty',
+  ],
+
+  steps: () => [
+    raiseOutputWithoutDependency({
+      dependency: 'thing',
+      output: input.value({
+        '#contributionTarget': null,
+        '#contributionProperty': null,
+      }),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: 'thingProperty',
+      output: input.value({
+        '#contributionTarget': null,
+        '#contributionProperty': null,
+      }),
+    }),
+
+    {
+      dependencies: ['thing', 'thingProperty'],
+
+      compute: (continuation, {
+        ['thing']: thing,
+        ['thingProperty']: thingProperty,
+      }) => continuation({
+        ['#contributionTarget']:
+          thing.constructor[Symbol.for('Thing.referenceType')],
+
+        ['#contributionProperty']:
+          thingProperty,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/things/contribution/withMatchingContributionPresets.js b/src/data/composite/things/contribution/withMatchingContributionPresets.js
new file mode 100644
index 00000000..09454164
--- /dev/null
+++ b/src/data/composite/things/contribution/withMatchingContributionPresets.js
@@ -0,0 +1,70 @@
+import {input, templateCompositeFrom} from '#composite';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertyFromObject} from '#composite/data';
+
+import withContributionContext from './withContributionContext.js';
+
+export default templateCompositeFrom({
+  annotation: `withMatchingContributionPresets`,
+
+  outputs: ['#matchingContributionPresets'],
+
+  steps: () => [
+    withPropertyFromObject({
+      object: 'thing',
+      property: input.value('wikiInfo'),
+      internal: input.value(true),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#thing.wikiInfo',
+      output: input.value({
+        '#matchingContributionPresets': null,
+      }),
+    }),
+
+    withPropertyFromObject({
+      object: '#thing.wikiInfo',
+      property: input.value('contributionPresets'),
+    }).outputs({
+      '#thing.wikiInfo.contributionPresets': '#contributionPresets',
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#contributionPresets',
+      mode: input.value('empty'),
+      output: input.value({
+        '#matchingContributionPresets': [],
+      }),
+    }),
+
+    withContributionContext(),
+
+    {
+      dependencies: [
+        '#contributionPresets',
+        '#contributionTarget',
+        '#contributionProperty',
+        'annotation',
+      ],
+
+      compute: (continuation, {
+        ['#contributionPresets']: presets,
+        ['#contributionTarget']: target,
+        ['#contributionProperty']: property,
+        ['annotation']: annotation,
+      }) => continuation({
+        ['#matchingContributionPresets']:
+          presets
+            .filter(preset =>
+              preset.context[0] === target &&
+              preset.context.slice(1).includes(property) &&
+              // For now, only match if the annotation is a complete match.
+              // Partial matches (e.g. because the contribution includes "two"
+              // annotations, separated by commas) don't count.
+              preset.annotation === annotation),
+      })
+    },
+  ],
+});
diff --git a/src/data/composite/things/track/index.js b/src/data/composite/things/track/index.js
index 8959de9f..714858a0 100644
--- a/src/data/composite/things/track/index.js
+++ b/src/data/composite/things/track/index.js
@@ -1,12 +1,16 @@
 export {default as exitWithoutUniqueCoverArt} from './exitWithoutUniqueCoverArt.js';
 export {default as inferredAdditionalNameList} from './inferredAdditionalNameList.js';
+export {default as inheritContributionListFromOriginalRelease} from './inheritContributionListFromOriginalRelease.js';
 export {default as inheritFromOriginalRelease} from './inheritFromOriginalRelease.js';
 export {default as sharedAdditionalNameList} from './sharedAdditionalNameList.js';
 export {default as trackReverseReferenceList} from './trackReverseReferenceList.js';
 export {default as withAlbum} from './withAlbum.js';
 export {default as withAlwaysReferenceByDirectory} from './withAlwaysReferenceByDirectory.js';
 export {default as withContainingTrackSection} from './withContainingTrackSection.js';
+export {default as withDate} from './withDate.js';
 export {default as withHasUniqueCoverArt} from './withHasUniqueCoverArt.js';
+export {default as withOriginalRelease} from './withOriginalRelease.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 withTrackArtDate} from './withTrackArtDate.js';
diff --git a/src/data/composite/things/track/inheritContributionListFromOriginalRelease.js b/src/data/composite/things/track/inheritContributionListFromOriginalRelease.js
new file mode 100644
index 00000000..f4ae3ddb
--- /dev/null
+++ b/src/data/composite/things/track/inheritContributionListFromOriginalRelease.js
@@ -0,0 +1,44 @@
+// Like inheritFromOriginalRelease, but tuned for contributions.
+// Recontextualized contributions for this track.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {exposeDependency, raiseOutputWithoutDependency}
+  from '#composite/control-flow';
+import {withRecontextualizedContributionList, withRedatedContributionList}
+  from '#composite/wiki-data';
+
+import withDate from './withDate.js';
+import withPropertyFromOriginalRelease
+  from './withPropertyFromOriginalRelease.js';
+
+export default templateCompositeFrom({
+  annotation: `inheritContributionListFromOriginalRelease`,
+
+  steps: () => [
+    withPropertyFromOriginalRelease({
+      property: input.thisProperty(),
+      notFoundValue: input.value([]),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#isRerelease',
+      mode: input.value('falsy'),
+    }),
+
+    withRecontextualizedContributionList({
+      list: '#originalValue',
+    }),
+
+    withDate(),
+
+    withRedatedContributionList({
+      list: '#originalValue',
+      date: '#date',
+    }),
+
+    exposeDependency({
+      dependency: '#originalValue',
+    }),
+  ],
+});
diff --git a/src/data/composite/things/track/withContainingTrackSection.js b/src/data/composite/things/track/withContainingTrackSection.js
index eaac14de..2c42709b 100644
--- a/src/data/composite/things/track/withContainingTrackSection.js
+++ b/src/data/composite/things/track/withContainingTrackSection.js
@@ -30,7 +30,6 @@ export default templateCompositeFrom({
 
       compute: (continuation, {
         [input.myself()]: track,
-        [input('notFoundMode')]: notFoundMode,
         ['#album.trackSections']: trackSections,
       }) => continuation({
         ['#trackSection']:
diff --git a/src/data/composite/things/track/withDate.js b/src/data/composite/things/track/withDate.js
new file mode 100644
index 00000000..b5a770e9
--- /dev/null
+++ b/src/data/composite/things/track/withDate.js
@@ -0,0 +1,34 @@
+// Gets the track's own date. This is either its dateFirstReleased property
+// or, if unset, the album's date.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import withPropertyFromAlbum from './withPropertyFromAlbum.js';
+
+export default templateCompositeFrom({
+  annotation: `withDate`,
+
+  outputs: ['#date'],
+
+  steps: () => [
+    {
+      dependencies: ['dateFirstReleased'],
+      compute: (continuation, {dateFirstReleased}) =>
+        (dateFirstReleased
+          ? continuation.raiseOutput({'#date': dateFirstReleased})
+          : continuation()),
+    },
+
+    withPropertyFromAlbum({
+      property: input.value('date'),
+    }),
+
+    {
+      dependencies: ['#album.date'],
+      compute: (continuation, {['#album.date']: albumDate}) =>
+        (albumDate
+          ? continuation.raiseOutput({'#date': albumDate})
+          : continuation.raiseOutput({'#date': null})),
+    },
+  ],
+})
diff --git a/src/data/composite/things/track/withHasUniqueCoverArt.js b/src/data/composite/things/track/withHasUniqueCoverArt.js
index 96078d5f..f7e65f25 100644
--- a/src/data/composite/things/track/withHasUniqueCoverArt.js
+++ b/src/data/composite/things/track/withHasUniqueCoverArt.js
@@ -29,7 +29,10 @@ export default templateCompositeFrom({
           : continuation()),
     },
 
-    withResolvedContribs({from: 'coverArtistContribs'}),
+    withResolvedContribs({
+      from: 'coverArtistContribs',
+      date: input.value(null),
+    }),
 
     {
       dependencies: ['#resolvedContribs'],
diff --git a/src/data/composite/things/track/withTrackArtDate.js b/src/data/composite/things/track/withTrackArtDate.js
new file mode 100644
index 00000000..e2c4d8bc
--- /dev/null
+++ b/src/data/composite/things/track/withTrackArtDate.js
@@ -0,0 +1,80 @@
+// 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';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+import withDate from './withDate.js';
+import withHasUniqueCoverArt from './withHasUniqueCoverArt.js';
+import withPropertyFromAlbum from './withPropertyFromAlbum.js';
+
+export default templateCompositeFrom({
+  annotation: `withTrackArtDate`,
+
+  inputs: {
+    from: input({
+      validate: isDate,
+      defaultDependency: 'coverArtDate',
+      acceptsNull: true,
+    }),
+
+    fallback: input({
+      type: 'boolean',
+      defaultValue: false,
+    }),
+  },
+
+  outputs: ['#trackArtDate'],
+
+  steps: () => [
+    withHasUniqueCoverArt(),
+
+    raiseOutputWithoutDependency({
+      dependency: '#hasUniqueCoverArt',
+      mode: input.value('falsy'),
+      output: input.value({'#trackArtDate': null}),
+    }),
+
+    {
+      dependencies: [input('from')],
+      compute: (continuation, {
+        [input('from')]: from,
+      }) =>
+        (from
+          ? continuation.raiseOutput({'#trackArtDate': from})
+          : continuation()),
+    },
+
+    withPropertyFromAlbum({
+      property: input.value('trackArtDate'),
+    }),
+
+    {
+      dependencies: [
+        '#album.trackArtDate',
+        input('fallback'),
+      ],
+
+      compute: (continuation, {
+        ['#album.trackArtDate']: albumTrackArtDate,
+        [input('fallback')]: fallback,
+      }) =>
+        (albumTrackArtDate
+          ? continuation.raiseOutput({'#trackArtDate': albumTrackArtDate})
+       : fallback
+          ? continuation()
+          : continuation.raiseOutput({'#trackArtDate': null})),
+    },
+
+    withDate().outputs({
+      '#date': '#trackArtDate',
+    }),
+  ],
+});
diff --git a/src/data/composite/wiki-data/exitWithoutContribs.js b/src/data/composite/wiki-data/exitWithoutContribs.js
index 2c8219fc..cf52950d 100644
--- a/src/data/composite/wiki-data/exitWithoutContribs.js
+++ b/src/data/composite/wiki-data/exitWithoutContribs.js
@@ -24,6 +24,7 @@ export default templateCompositeFrom({
   steps: () => [
     withResolvedContribs({
       from: input('contribs'),
+      date: input.value(null),
     }),
 
     // TODO: Fairly certain exitWithoutDependency would be sufficient here.
diff --git a/src/data/composite/wiki-data/index.js b/src/data/composite/wiki-data/index.js
index 15ebaffa..5f17ca3a 100644
--- a/src/data/composite/wiki-data/index.js
+++ b/src/data/composite/wiki-data/index.js
@@ -6,9 +6,14 @@
 
 export {default as exitWithoutContribs} from './exitWithoutContribs.js';
 export {default as inputWikiData} from './inputWikiData.js';
+export {default as withClonedThings} from './withClonedThings.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 withDirectoryFromName} from './withDirectoryFromName.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 withResolvedContribs} from './withResolvedContribs.js';
 export {default as withResolvedReference} from './withResolvedReference.js';
 export {default as withResolvedReferenceList} from './withResolvedReferenceList.js';
diff --git a/src/data/composite/wiki-data/withClonedThings.js b/src/data/composite/wiki-data/withClonedThings.js
new file mode 100644
index 00000000..9af6aa84
--- /dev/null
+++ b/src/data/composite/wiki-data/withClonedThings.js
@@ -0,0 +1,68 @@
+// Clones all the things in a list. If the 'assign' input is provided,
+// all new things are assigned the same specified properties. If the
+// 'assignEach' input is provided, each new thing is assigned the
+// corresponding properties.
+
+import CacheableObject from '#cacheable-object';
+import {input, templateCompositeFrom} from '#composite';
+import {isObject, sparseArrayOf} from '#validators';
+
+import {withMappedList} from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: `withClonedThings`,
+
+  inputs: {
+    things: input({type: 'array'}),
+
+    assign: input({
+      type: 'object',
+      defaultValue: null,
+    }),
+
+    assignEach: input({
+      validate: sparseArrayOf(isObject),
+      defaultValue: null,
+    }),
+  },
+
+  outputs: ['#clonedThings'],
+
+  steps: () => [
+    {
+      dependencies: [input('assign'), input('assignEach')],
+      compute: (continuation, {
+        [input('assign')]: assign,
+        [input('assignEach')]: assignEach,
+      }) => continuation({
+        ['#assignmentMap']:
+          (index) =>
+            (assign && assignEach
+              ? {...assignEach[index] ?? {}, ...assign}
+           : assignEach
+              ? assignEach[index] ?? {}
+              : assign ?? {}),
+      }),
+    },
+
+    {
+      dependencies: ['#assignmentMap'],
+      compute: (continuation, {
+        ['#assignmentMap']: assignmentMap,
+      }) => continuation({
+        ['#cloningMap']:
+          (thing, index) =>
+            Object.assign(
+              CacheableObject.clone(thing),
+              assignmentMap(index)),
+      }),
+    },
+
+    withMappedList({
+      list: input('things'),
+      map: '#cloningMap',
+    }).outputs({
+      '#mappedList': '#clonedThings',
+    }),
+  ],
+});
diff --git a/src/data/composite/wiki-data/withContributionListSums.js b/src/data/composite/wiki-data/withContributionListSums.js
new file mode 100644
index 00000000..b4f36361
--- /dev/null
+++ b/src/data/composite/wiki-data/withContributionListSums.js
@@ -0,0 +1,95 @@
+// Gets the total duration and contribution count from a list of contributions,
+// respecting their `countInContributionTotals` and `countInDurationTotals`
+// flags.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import {
+  withFilteredList,
+  withPropertiesFromList,
+  withPropertyFromList,
+  withSum,
+  withUniqueItemsOnly,
+} from '#composite/data';
+
+export default templateCompositeFrom({
+  annotation: `withContributionListSums`,
+
+  inputs: {
+    list: input({type: 'array'}),
+  },
+
+  outputs: [
+    '#contributionListCount',
+    '#contributionListDuration',
+  ],
+
+  steps: () => [
+    withPropertiesFromList({
+      list: input('list'),
+      properties: input.value([
+        'countInContributionTotals',
+        'countInDurationTotals',
+      ]),
+    }),
+
+    withFilteredList({
+      list: input('list'),
+      filter: '#list.countInContributionTotals',
+    }).outputs({
+      '#filteredList': '#contributionsForCounting',
+    }),
+
+    withFilteredList({
+      list: input('list'),
+      filter: '#list.countInDurationTotals',
+    }).outputs({
+      '#filteredList': '#contributionsForDuration',
+    }),
+
+    {
+      dependencies: ['#contributionsForCounting'],
+      compute: (continuation, {
+        ['#contributionsForCounting']: contributionsForCounting,
+      }) => continuation({
+        ['#count']:
+          contributionsForCounting.length,
+      }),
+    },
+
+    withPropertyFromList({
+      list: '#contributionsForDuration',
+      property: input.value('thing'),
+    }),
+
+    // Don't double-up the durations for a track where the artist has multiple
+    // contributions.
+    withUniqueItemsOnly({
+      list: '#contributionsForDuration.thing',
+    }),
+
+    withPropertyFromList({
+      list: '#contributionsForDuration.thing',
+      property: input.value('duration'),
+    }).outputs({
+      '#contributionsForDuration.thing.duration': '#durationValues',
+    }),
+
+    withSum({
+      values: '#durationValues',
+    }).outputs({
+      '#sum': '#duration',
+    }),
+
+    {
+      dependencies: ['#count', '#duration'],
+      compute: (continuation, {
+        ['#count']: count,
+        ['#duration']: duration,
+      }) => continuation({
+        ['#contributionListCount']: count,
+        ['#contributionListDuration']: duration,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/withCoverArtDate.js b/src/data/composite/wiki-data/withCoverArtDate.js
new file mode 100644
index 00000000..0c644c77
--- /dev/null
+++ b/src/data/composite/wiki-data/withCoverArtDate.js
@@ -0,0 +1,70 @@
+// 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';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+
+import withResolvedContribs from './withResolvedContribs.js';
+
+export default templateCompositeFrom({
+  annotation: `withCoverArtDate`,
+
+  inputs: {
+    from: input({
+      validate: isDate,
+      defaultDependency: 'coverArtDate',
+      acceptsNull: true,
+    }),
+
+    fallback: input({
+      type: 'boolean',
+      defaultValue: false,
+    }),
+  },
+
+  outputs: ['#coverArtDate'],
+
+  steps: () => [
+    withResolvedContribs({
+      from: 'coverArtistContribs',
+      date: input.value(null),
+    }),
+
+    raiseOutputWithoutDependency({
+      dependency: '#resolvedContribs',
+      mode: input.value('empty'),
+      output: input.value({'#coverArtDate': null}),
+    }),
+
+    {
+      dependencies: [input('from')],
+      compute: (continuation, {
+        [input('from')]: from,
+      }) =>
+        (from
+          ? continuation.raiseOutput({'#coverArtDate': from})
+          : continuation()),
+    },
+
+    {
+      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})),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/withRecontextualizedContributionList.js b/src/data/composite/wiki-data/withRecontextualizedContributionList.js
new file mode 100644
index 00000000..d2401eac
--- /dev/null
+++ b/src/data/composite/wiki-data/withRecontextualizedContributionList.js
@@ -0,0 +1,101 @@
+// Clones all the contributions in a list, with thing and thingProperty both
+// updated to match the current thing. Overwrites the provided dependency.
+// Optionally updates artistProperty as well. Doesn't do anything if
+// the provided dependency is null.
+//
+// See also:
+//  - withRedatedContributionList
+//
+
+import {input, templateCompositeFrom} from '#composite';
+import {isStringNonEmpty} from '#validators';
+
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withClonedThings} from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `withRecontextualizedContributionList`,
+
+  inputs: {
+    list: input.staticDependency({
+      type: 'array',
+      acceptsNull: true,
+    }),
+
+    artistProperty: input({
+      validate: isStringNonEmpty,
+      defaultValue: null,
+    }),
+  },
+
+  outputs: ({
+    [input.staticDependency('list')]: list,
+  }) => [list],
+
+  steps: () => [
+    // TODO: Is raiseOutputWithoutDependency workable here?
+    // Is it true that not specifying any output wouldn't overwrite
+    // the provided dependency?
+    {
+      dependencies: [
+        input.staticDependency('list'),
+        input('list'),
+      ],
+
+      compute: (continuation, {
+        [input.staticDependency('list')]: dependency,
+        [input('list')]: list,
+      }) =>
+        (list
+          ? continuation()
+          : continuation.raiseOutput({
+              [dependency]: list,
+            })),
+    },
+
+    {
+      dependencies: [
+        input.myself(),
+        input.thisProperty(),
+        input('artistProperty'),
+      ],
+
+      compute: (continuation, {
+        [input.myself()]: myself,
+        [input.thisProperty()]: thisProperty,
+        [input('artistProperty')]: artistProperty,
+      }) => continuation({
+        ['#assignment']:
+          Object.assign(
+            {thing: myself},
+            {thingProperty: thisProperty},
+
+            (artistProperty
+              ? {artistProperty}
+              : {})),
+      }),
+    },
+
+    withClonedThings({
+      things: input('list'),
+      assign: '#assignment',
+    }).outputs({
+      '#clonedThings': '#newContributions',
+    }),
+
+    {
+      dependencies: [
+        input.staticDependency('list'),
+        '#newContributions',
+      ],
+
+      compute: (continuation, {
+        [input.staticDependency('list')]: listDependency,
+        ['#newContributions']: newContributions,
+      }) => continuation({
+        [listDependency]:
+          newContributions,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/withRedatedContributionList.js b/src/data/composite/wiki-data/withRedatedContributionList.js
new file mode 100644
index 00000000..12f3e16b
--- /dev/null
+++ b/src/data/composite/wiki-data/withRedatedContributionList.js
@@ -0,0 +1,127 @@
+// Clones all the contributions in a list, with date updated to the provided
+// value. Overwrites the provided dependency. Doesn't do anything if the
+// provided dependency is null, or the provided date is null.
+//
+// If 'override' is true (the default), then so long as the provided date has
+// a value at all, it's always written onto the (cloned) contributions.
+//
+// If 'override' is false, and any of the contributions were already dated,
+// those will keep their existing dates.
+//
+// See also:
+//  - withRecontextualizedContributionList
+//
+
+import {input, templateCompositeFrom} from '#composite';
+import {isDate} from '#validators';
+
+import {withMappedList, withPropertyFromList} from '#composite/data';
+import {withClonedThings} from '#composite/wiki-data';
+
+export default templateCompositeFrom({
+  annotation: `withRedatedContributionList`,
+
+  inputs: {
+    list: input.staticDependency({
+      type: 'array',
+      acceptsNull: true,
+    }),
+
+    date: input({
+      validate: isDate,
+      acceptsNull: true,
+    }),
+
+    override: input({
+      type: 'boolean',
+      defaultValue: true,
+    }),
+  },
+
+  outputs: ({
+    [input.staticDependency('list')]: list,
+  }) => [list],
+
+  steps: () => [
+    // TODO: Is raiseOutputWithoutDependency workable here?
+    // Is it true that not specifying any output wouldn't overwrite
+    // the provided dependency?
+    {
+      dependencies: [
+        input.staticDependency('list'),
+        input('list'),
+        input('date'),
+      ],
+
+      compute: (continuation, {
+        [input.staticDependency('list')]: dependency,
+        [input('list')]: list,
+        [input('date')]: date,
+      }) =>
+        (list && date
+          ? continuation()
+          : continuation.raiseOutput({
+              [dependency]: list,
+            })),
+    },
+
+    withPropertyFromList({
+      list: input('list'),
+      property: input.value('date'),
+    }).outputs({
+      '#list.date': '#existingDates',
+    }),
+
+    {
+      dependencies: [
+        input('date'),
+        input('override'),
+        '#existingDates',
+      ],
+
+      compute: (continuation, {
+        [input('date')]: date,
+        [input('override')]: override,
+        '#existingDates': existingDates,
+      }) => continuation({
+        ['#assignmentMap']:
+          // TODO: Should be mapping over withIndicesFromList
+          (_, index) =>
+            (!override && existingDates[index]
+              ? {date: existingDates[index]}
+           : date
+              ? {date}
+              : {}),
+      }),
+    },
+
+    withMappedList({
+      list: input('list'),
+      map: '#assignmentMap',
+    }).outputs({
+      '#mappedList': '#assignment',
+    }),
+
+    withClonedThings({
+      things: input('list'),
+      assignEach: '#assignment',
+    }).outputs({
+      '#clonedThings': '#newContributions',
+    }),
+
+    {
+      dependencies: [
+        input.staticDependency('list'),
+        '#newContributions',
+      ],
+
+      compute: (continuation, {
+        [input.staticDependency('list')]: listDependency,
+        ['#newContributions']: newContributions,
+      }) => continuation({
+        [listDependency]:
+          newContributions,
+      }),
+    },
+  ],
+});
diff --git a/src/data/composite/wiki-data/withResolvedContribs.js b/src/data/composite/wiki-data/withResolvedContribs.js
index 95266382..b5d7255b 100644
--- a/src/data/composite/wiki-data/withResolvedContribs.js
+++ b/src/data/composite/wiki-data/withResolvedContribs.js
@@ -7,17 +7,11 @@
 import {input, templateCompositeFrom} from '#composite';
 import find from '#find';
 import {filterMultipleArrays, stitchArrays} from '#sugar';
-import {is, isContributionList} from '#validators';
+import thingConstructors from '#things';
+import {is, isContributionList, isDate, isStringNonEmpty} from '#validators';
 
-import {
-  raiseOutputWithoutDependency,
-} from '#composite/control-flow';
-
-import {
-  withPropertiesFromList,
-} from '#composite/data';
-
-import withResolvedReferenceList from './withResolvedReferenceList.js';
+import {raiseOutputWithoutDependency} from '#composite/control-flow';
+import {withPropertiesFromList} from '#composite/data';
 
 export default templateCompositeFrom({
   annotation: `withResolvedContribs`,
@@ -28,10 +22,25 @@ export default templateCompositeFrom({
       acceptsNull: true,
     }),
 
+    date: input({
+      validate: isDate,
+      acceptsNull: true,
+    }),
+
     notFoundMode: input({
       validate: is('exit', 'filter', 'null'),
       defaultValue: 'null',
     }),
+
+    thingProperty: input({
+      validate: isStringNonEmpty,
+      defaultValue: null,
+    }),
+
+    artistProperty: input({
+      validate: isStringNonEmpty,
+      defaultValue: null,
+    }),
   },
 
   outputs: ['#resolvedContribs'],
@@ -45,34 +54,96 @@ export default templateCompositeFrom({
       }),
     }),
 
+    {
+      dependencies: [
+        input('thingProperty'),
+        input.staticDependency('from'),
+      ],
+
+      compute: (continuation, {
+        [input('thingProperty')]: thingProperty,
+        [input.staticDependency('from')]: fromDependency,
+      }) => continuation({
+        ['#thingProperty']:
+          (thingProperty
+            ? thingProperty
+         : !fromDependency?.startsWith('#')
+            ? fromDependency
+            : null),
+      }),
+    },
+
     withPropertiesFromList({
       list: input('from'),
       properties: input.value(['artist', 'annotation']),
       prefix: input.value('#contribs'),
     }),
 
-    withResolvedReferenceList({
-      list: '#contribs.artist',
-      data: 'artistData',
-      find: input.value(find.artist),
-      notFoundMode: input('notFoundMode'),
-    }).outputs({
-      ['#resolvedReferenceList']: '#contribs.artist',
-    }),
-
     {
-      dependencies: ['#contribs.artist', '#contribs.annotation'],
+      dependencies: [
+        '#contribs.artist',
+        '#contribs.annotation',
+        input('date'),
+      ],
 
       compute(continuation, {
         ['#contribs.artist']: artist,
         ['#contribs.annotation']: annotation,
+        [input('date')]: date,
       }) {
         filterMultipleArrays(artist, annotation, (artist, _annotation) => artist);
+
         return continuation({
-          ['#resolvedContribs']:
-            stitchArrays({artist, annotation}),
+          ['#details']:
+            stitchArrays({artist, annotation})
+              .map(details => ({
+                ...details,
+                date: date ?? null,
+              })),
         });
       },
     },
+
+    {
+      dependencies: [
+        '#details',
+        '#thingProperty',
+        input('artistProperty'),
+        input.myself(),
+      ],
+
+      compute: (continuation, {
+        ['#details']: details,
+        ['#thingProperty']: thingProperty,
+        [input('artistProperty')]: artistProperty,
+        [input.myself()]: myself,
+      }) => continuation({
+        ['#contributions']:
+          details.map(details => {
+            const contrib = new thingConstructors.Contribution();
+
+            Object.assign(contrib, {
+              ...details,
+              thing: myself,
+              thingProperty: thingProperty,
+              artistProperty: artistProperty,
+            });
+
+            return contrib;
+          }),
+      }),
+    },
+
+    {
+      dependencies: ['#contributions'],
+
+      compute: (continuation, {
+        ['#contributions']: contributions,
+      }) => continuation({
+        ['#resolvedContribs']:
+          contributions
+            .filter(contrib => contrib.artist),
+      }),
+    },
   ],
 });
diff --git a/src/data/composite/wiki-data/withReverseContributionList.js b/src/data/composite/wiki-data/withReverseContributionList.js
index 91e125e4..63e712bb 100644
--- a/src/data/composite/wiki-data/withReverseContributionList.js
+++ b/src/data/composite/wiki-data/withReverseContributionList.js
@@ -1,6 +1,6 @@
 // Analogous implementation for withReverseReferenceList, for contributions.
-// This is all duplicate code and both should be ported to the same underlying
-// data form later on.
+// This is mostly duplicate code and both should be ported to the same
+// underlying data form later on.
 //
 // This implementation uses a global cache (via WeakMap) to attempt to speed
 // up subsequent similar accesses.
@@ -10,9 +10,11 @@
 // is used, a fresh cache will always be created.
 
 import {input, templateCompositeFrom} from '#composite';
+import {stitchArrays} from '#sugar';
 
 import {exitWithoutDependency, raiseOutputWithoutDependency}
   from '#composite/control-flow';
+import {withFlattenedList, withMappedList} from '#composite/data';
 
 import inputWikiData from './inputWikiData.js';
 
@@ -33,6 +35,8 @@ export default templateCompositeFrom({
   outputs: ['#reverseContributionList'],
 
   steps: () => [
+    // Common behavior --
+
     // Early exit with an empty array if the data list isn't available.
     exitWithoutDependency({
       dependency: input('data'),
@@ -46,46 +50,122 @@ export default templateCompositeFrom({
       output: input.value({'#reverseContributionList': []}),
     }),
 
+    // Check for an existing cache record which corresponds to this
+    // input('list') 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.myself(), input('data'), input('list')],
+      dependencies: [input('list'), input('data'), input.myself()],
 
       compute: (continuation, {
-        [input.myself()]: myself,
-        [input('data')]: data,
         [input('list')]: list,
+        [input('data')]: data,
+        [input.myself()]: myself,
       }) => {
         if (!caches.has(list)) {
-          caches.set(list, new WeakMap());
+          const cache = new WeakMap();
+          caches.set(list, cache);
+
+          const cacheRecord = new WeakMap();
+          cache.set(data, cacheRecord);
+
+          return continuation({
+            ['#cacheRecord']: cacheRecord,
+          });
         }
 
         const cache = caches.get(list);
 
         if (!cache.has(data)) {
           const cacheRecord = new WeakMap();
+          cache.set(data, cacheRecord);
+
+          return continuation({
+            ['#cacheRecord']: cacheRecord,
+          });
+        }
+
+        return continuation.raiseOutput({
+          ['#reverseContributionList']:
+            cache.get(data).get(myself) ?? [],
+        });
+      },
+    },
+
+    // Unique behavior for contribution lists --
+
+    {
+      dependencies: [input('list')],
+      compute: (continuation, {
+        [input('list')]: list,
+      }) => continuation({
+        ['#contributionListMap']:
+          thing => thing[list],
+      }),
+    },
+
+    withMappedList({
+      list: input('data'),
+      map: '#contributionListMap',
+    }).outputs({
+      '#mappedList': '#contributionLists',
+    }),
 
-          for (const referencingThing of data) {
-            const referenceList = referencingThing[list];
+    withFlattenedList({
+      list: '#contributionLists',
+    }).outputs({
+      '#flattenedList': '#referencingThings',
+    }),
 
-            // Destructuring {artist} is the only unique part of the
-            // withReverseContributionList implementation, compared to
-            // withReverseReferneceList.
-            for (const {artist: referencedThing} of referenceList) {
+    withMappedList({
+      list: '#referencingThings',
+      map: input.value(contrib => [contrib.artist]),
+    }).outputs({
+      '#mappedList': '#referencedThings',
+    }),
+
+    // Common behavior --
+
+    // Actually fill in the cache record. Since we're building up a *reverse*
+    // reference list, track connections in terms of the referenced thing.
+    // No newly-provided dependencies here since we're mutating the cache
+    // record, which is properly in store and will probably be reused in the
+    // future (and certainly in the next step).
+    {
+      dependencies: ['#cacheRecord', '#referencingThings', '#referencedThings'],
+      compute: (continuation, {
+        ['#cacheRecord']: cacheRecord,
+        ['#referencingThings']: referencingThings,
+        ['#referencedThings']: referencedThings,
+      }) => {
+        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]);
               }
             }
-          }
+          });
 
-          cache.set(data, cacheRecord);
-        }
-
-        return continuation({
-          ['#reverseContributionList']:
-            cache.get(data).get(myself) ?? [],
-        });
+        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({
+        ['#reverseContributionList']:
+          cacheRecord.get(myself) ?? [],
+      }),
+    },
   ],
 });
diff --git a/src/data/composite/wiki-data/withReverseReferenceList.js b/src/data/composite/wiki-data/withReverseReferenceList.js
index 8cd540a5..1f8c082f 100644
--- a/src/data/composite/wiki-data/withReverseReferenceList.js
+++ b/src/data/composite/wiki-data/withReverseReferenceList.js
@@ -12,9 +12,11 @@
 // so any changes should be reflected there (until these are combined).
 
 import {input, templateCompositeFrom} from '#composite';
+import {stitchArrays} from '#sugar';
 
 import {exitWithoutDependency, raiseOutputWithoutDependency}
   from '#composite/control-flow';
+import {withMappedList} from '#composite/data';
 
 import inputWikiData from './inputWikiData.js';
 
@@ -35,6 +37,8 @@ export default templateCompositeFrom({
   outputs: ['#reverseReferenceList'],
 
   steps: () => [
+    // Common behavior --
+
     // Early exit with an empty array if the data list isn't available.
     exitWithoutDependency({
       dependency: input('data'),
@@ -48,42 +52,119 @@ export default templateCompositeFrom({
       output: input.value({'#reverseReferenceList': []}),
     }),
 
+    // Check for an existing cache record which corresponds to this
+    // input('list') 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.myself(), input('data'), input('list')],
+      dependencies: [input('list'), input('data'), input.myself()],
 
       compute: (continuation, {
-        [input.myself()]: myself,
-        [input('data')]: data,
         [input('list')]: list,
+        [input('data')]: data,
+        [input.myself()]: myself,
       }) => {
         if (!caches.has(list)) {
-          caches.set(list, new WeakMap());
+          const cache = new WeakMap();
+          caches.set(list, cache);
+
+          const cacheRecord = new WeakMap();
+          cache.set(data, cacheRecord);
+
+          return continuation({
+            ['#cacheRecord']: cacheRecord,
+          });
         }
 
         const cache = caches.get(list);
 
         if (!cache.has(data)) {
           const cacheRecord = new WeakMap();
+          cache.set(data, cacheRecord);
+
+          return continuation({
+            ['#cacheRecord']: cacheRecord,
+          });
+        }
+
+        return continuation.raiseOutput({
+          ['#reverseReferenceList']:
+            cache.get(data).get(myself) ?? [],
+        });
+      },
+    },
+
+    // Unique behavior for reference lists --
+
+    {
+      dependencies: [input('list')],
+      compute: (continuation, {
+        [input('list')]: list,
+      }) => continuation({
+        ['#referenceMap']:
+          thing => thing[list],
+      }),
+    },
+
+    withMappedList({
+      list: input('data'),
+      map: '#referenceMap',
+    }).outputs({
+      '#mappedList': '#referencedThings',
+    }),
+
+    {
+      dependencies: [input('data')],
+      compute: (continuation, {
+        [input('data')]: data,
+      }) => continuation({
+        ['#referencingThings']:
+          data,
+      }),
+    },
+
+    // Common behavior --
 
-          for (const referencingThing of data) {
-            const referenceList = referencingThing[list];
-            for (const referencedThing of referenceList) {
+    // Actually fill in the cache record. Since we're building up a *reverse*
+    // reference list, track connections in terms of the referenced thing.
+    // No newly-provided dependencies here since we're mutating the cache
+    // record, which is properly in store and will probably be reused in the
+    // future (and certainly in the next step).
+    {
+      dependencies: ['#cacheRecord', '#referencingThings', '#referencedThings'],
+      compute: (continuation, {
+        ['#cacheRecord']: cacheRecord,
+        ['#referencingThings']: referencingThings,
+        ['#referencedThings']: referencedThings,
+      }) => {
+        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]);
               }
             }
-          }
+          });
 
-          cache.set(data, cacheRecord);
-        }
-
-        return continuation({
-          ['#reverseReferenceList']:
-            cache.get(data).get(myself) ?? [],
-        });
+        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({
+        ['#reverseReferenceList']:
+          cacheRecord.get(myself) ?? [],
+      }),
+    },
   ],
 });
diff --git a/src/data/composite/wiki-properties/contributionList.js b/src/data/composite/wiki-properties/contributionList.js
index aad12a2d..d9a6b417 100644
--- a/src/data/composite/wiki-properties/contributionList.js
+++ b/src/data/composite/wiki-properties/contributionList.js
@@ -15,7 +15,7 @@
 //
 
 import {input, templateCompositeFrom} from '#composite';
-import {isContributionList} from '#validators';
+import {isContributionList, isDate, isStringNonEmpty} from '#validators';
 
 import {exposeConstant, exposeDependencyOrContinue} from '#composite/control-flow';
 import {withResolvedContribs} from '#composite/wiki-data';
@@ -25,11 +25,34 @@ export default templateCompositeFrom({
 
   compose: false,
 
+  inputs: {
+    date: input({
+      validate: isDate,
+      acceptsNull: true,
+    }),
+
+    artistProperty: input({
+      validate: isStringNonEmpty,
+      defaultValue: null,
+    }),
+  },
+
   update: {validate: isContributionList},
 
   steps: () => [
-    withResolvedContribs({from: input.updateValue()}),
-    exposeDependencyOrContinue({dependency: '#resolvedContribs'}),
-    exposeConstant({value: input.value([])}),
+    withResolvedContribs({
+      from: input.updateValue(),
+      thingProperty: input.thisProperty(),
+      artistProperty: input('artistProperty'),
+      date: input('date'),
+    }),
+
+    exposeDependencyOrContinue({
+      dependency: '#resolvedContribs',
+    }),
+
+    exposeConstant({
+      value: input.value([]),
+    }),
   ],
 });
diff --git a/src/data/composite/wiki-properties/index.js b/src/data/composite/wiki-properties/index.js
index 89cb6838..5328d17e 100644
--- a/src/data/composite/wiki-properties/index.js
+++ b/src/data/composite/wiki-properties/index.js
@@ -24,5 +24,6 @@ export {default as reverseReferenceList} from './reverseReferenceList.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 thing} from './thing.js';
 export {default as urls} from './urls.js';
 export {default as wikiData} from './wikiData.js';
diff --git a/src/data/composite/wiki-properties/thing.js b/src/data/composite/wiki-properties/thing.js
new file mode 100644
index 00000000..5b5d77dd
--- /dev/null
+++ b/src/data/composite/wiki-properties/thing.js
@@ -0,0 +1,31 @@
+// An individual Thing, provided directly rather than by reference.
+
+import {input, templateCompositeFrom} from '#composite';
+import {isThingClass, validateThing} from '#validators';
+
+export default templateCompositeFrom({
+  annotation: `wikiData`,
+
+  compose: false,
+
+  inputs: {
+    class: input.staticValue({
+      validate: isThingClass,
+      defaultValue: null,
+    }),
+  },
+
+  update: ({
+    [input.staticValue('class')]: thingClass,
+  }) => ({
+    validate:
+      validateThing({
+        referenceType:
+          (thingClass
+            ? thingClass[Symbol.for('Thing.referenceType')]
+            : ''),
+      }),
+  }),
+
+  steps: () => [],
+});
diff --git a/src/data/things/album.js b/src/data/things/album.js
index e9f55b2c..a0021946 100644
--- a/src/data/things/album.js
+++ b/src/data/things/album.js
@@ -18,8 +18,13 @@ import {parseAdditionalFiles, parseContributors, parseDate, parseDimensions}
 import {exitWithoutDependency, exposeDependency, exposeUpdateValueOrContinue}
   from '#composite/control-flow';
 import {withPropertyFromObject} from '#composite/data';
-import {exitWithoutContribs, withDirectory, withResolvedReference}
-  from '#composite/wiki-data';
+
+import {
+  exitWithoutContribs,
+  withDirectory,
+  withResolvedReference,
+  withCoverArtDate,
+} from '#composite/wiki-data';
 
 import {
   additionalFiles,
@@ -37,6 +42,7 @@ import {
   simpleDate,
   simpleString,
   singleReference,
+  thing,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
@@ -53,6 +59,7 @@ export class Album extends Thing {
     Group,
     Track,
     TrackSection,
+    WikiInfo,
   }) => ({
     // Update & expose
 
@@ -71,13 +78,16 @@ export class Album extends Thing {
     dateAddedToWiki: simpleDate(),
 
     coverArtDate: [
-      exitWithoutContribs({contribs: 'coverArtistContribs'}),
+      // TODO: Why does this fall back, but Track.coverArtDate doesn't?
+      withCoverArtDate({
+        from: input.updateValue({
+          validate: isDate,
+        }),
 
-      exposeUpdateValueOrContinue({
-        validate: input.value(isDate),
+        fallback: input.value(true),
       }),
 
-      exposeDependency({dependency: 'date'}),
+      exposeDependency({dependency: '#coverArtDate'}),
     ],
 
     coverArtFileExtension: [
@@ -130,11 +140,53 @@ export class Album extends Thing {
       find: input.value(find.unqualifiedTrackSection),
     }),
 
-    artistContribs: contributionList(),
-    coverArtistContribs: contributionList(),
-    trackCoverArtistContribs: contributionList(),
-    wallpaperArtistContribs: contributionList(),
-    bannerArtistContribs: contributionList(),
+    artistContribs: contributionList({
+      date: 'date',
+      artistProperty: input.value('albumArtistContributions'),
+    }),
+
+    coverArtistContribs: [
+      withCoverArtDate({
+        fallback: input.value(true),
+      }),
+
+      contributionList({
+        date: '#coverArtDate',
+        artistProperty: input.value('albumCoverArtistContributions'),
+      }),
+    ],
+
+    trackCoverArtistContribs: contributionList({
+      // May be null, indicating cover art was added for tracks on the date
+      // each track specifies, or else the track's own release date.
+      date: 'trackArtDate',
+
+      // This is the "correct" value, but it gets overwritten - with the same
+      // value - regardless.
+      artistProperty: input.value('trackCoverArtistContributions'),
+    }),
+
+    wallpaperArtistContribs: [
+      withCoverArtDate({
+        fallback: input.value(true),
+      }),
+
+      contributionList({
+        date: '#coverArtDate',
+        artistProperty: input.value('albumWallpaperArtistContributions'),
+      }),
+    ],
+
+    bannerArtistContribs: [
+      withCoverArtDate({
+        fallback: input.value(true),
+      }),
+
+      contributionList({
+        date: '#coverArtDate',
+        artistProperty: input.value('albumBannerArtistContributions'),
+      }),
+    ],
 
     groups: referenceList({
       class: input.value(Group),
@@ -173,6 +225,10 @@ export class Album extends Thing {
       class: input.value(TrackSection),
     }),
 
+    wikiInfo: thing({
+      class: input.value(WikiInfo),
+    }),
+
     // Expose only
 
     commentatorArtists: commentatorArtists(),
diff --git a/src/data/things/artist.js b/src/data/things/artist.js
index 841d652f..6d5e33c0 100644
--- a/src/data/things/artist.js
+++ b/src/data/things/artist.js
@@ -12,6 +12,7 @@ import Thing from '#thing';
 import {isName, validateArrayItems} from '#validators';
 import {getKebabCase} from '#wiki-data';
 
+import {exposeDependency} from '#composite/control-flow';
 import {withReverseContributionList} from '#composite/wiki-data';
 
 import {
@@ -27,6 +28,8 @@ import {
   wikiData,
 } from '#composite/wiki-properties';
 
+import {artistTotalDuration} from '#composite/things/artist';
+
 export class Artist extends Thing {
   static [Thing.referenceType] = 'artist';
   static [Thing.wikiDataArray] = 'artistData';
@@ -77,146 +80,52 @@ export class Artist extends Thing {
 
     // Expose only
 
-    tracksAsArtist: reverseContributionList({
+    trackArtistContributions: reverseContributionList({
       data: 'trackData',
       list: input.value('artistContribs'),
     }),
 
-    tracksAsContributor: reverseContributionList({
+    trackContributorContributions: reverseContributionList({
       data: 'trackData',
       list: input.value('contributorContribs'),
     }),
 
-    tracksAsCoverArtist: reverseContributionList({
+    trackCoverArtistContributions: reverseContributionList({
       data: 'trackData',
       list: input.value('coverArtistContribs'),
     }),
 
-    tracksAsAny: [
-      withReverseContributionList({
-        data: 'trackData',
-        list: input.value('artistContribs'),
-      }).outputs({
-        '#reverseContributionList': '#tracksAsArtist',
-      }),
-
-      withReverseContributionList({
-        data: 'trackData',
-        list: input.value('contributorContribs'),
-      }).outputs({
-        '#reverseContributionList': '#tracksAsContributor',
-      }),
-
-      withReverseContributionList({
-        data: 'trackData',
-        list: input.value('coverArtistContribs'),
-      }).outputs({
-        '#reverseContributionList': '#tracksAsCoverArtist',
-      }),
-
-      {
-        dependencies: [
-          '#tracksAsArtist',
-          '#tracksAsContributor',
-          '#tracksAsCoverArtist',
-        ],
-
-        compute: ({
-          ['#tracksAsArtist']: tracksAsArtist,
-          ['#tracksAsContributor']: tracksAsContributor,
-          ['#tracksAsCoverArtist']: tracksAsCoverArtist,
-        }) =>
-          unique([
-            ...tracksAsArtist,
-            ...tracksAsContributor,
-            ...tracksAsCoverArtist,
-          ]),
-      },
-    ],
-
     tracksAsCommentator: reverseReferenceList({
       data: 'trackData',
       list: input.value('commentatorArtists'),
     }),
 
-    albumsAsAlbumArtist: reverseContributionList({
+    albumArtistContributions: reverseContributionList({
       data: 'albumData',
       list: input.value('artistContribs'),
     }),
 
-    albumsAsCoverArtist: reverseContributionList({
+    albumCoverArtistContributions: reverseContributionList({
       data: 'albumData',
       list: input.value('coverArtistContribs'),
     }),
 
-    albumsAsWallpaperArtist: reverseContributionList({
+    albumWallpaperArtistContributions: reverseContributionList({
       data: 'albumData',
       list: input.value('wallpaperArtistContribs'),
     }),
 
-    albumsAsBannerArtist: reverseContributionList({
+    albumBannerArtistContributions: reverseContributionList({
       data: 'albumData',
       list: input.value('bannerArtistContribs'),
     }),
 
-    albumsAsAny: [
-      withReverseContributionList({
-        data: 'albumData',
-        list: input.value('artistContribs'),
-      }).outputs({
-        '#reverseContributionList': '#albumsAsArtist',
-      }),
-
-      withReverseContributionList({
-        data: 'albumData',
-        list: input.value('coverArtistContribs'),
-      }).outputs({
-        '#reverseContributionList': '#albumsAsCoverArtist',
-      }),
-
-      withReverseContributionList({
-        data: 'albumData',
-        list: input.value('wallpaperArtistContribs'),
-      }).outputs({
-        '#reverseContributionList': '#albumsAsWallpaperArtist',
-      }),
-
-      withReverseContributionList({
-        data: 'albumData',
-        list: input.value('bannerArtistContribs'),
-      }).outputs({
-        '#reverseContributionList': '#albumsAsBannerArtist',
-      }),
-
-      {
-        dependencies: [
-          '#albumsAsArtist',
-          '#albumsAsCoverArtist',
-          '#albumsAsWallpaperArtist',
-          '#albumsAsBannerArtist',
-        ],
-
-        compute: ({
-          ['#albumsAsArtist']: albumsAsArtist,
-          ['#albumsAsCoverArtist']: albumsAsCoverArtist,
-          ['#albumsAsWallpaperArtist']: albumsAsWallpaperArtist,
-          ['#albumsAsBannerArtist']: albumsAsBannerArtist,
-        }) =>
-          unique([
-            ...albumsAsArtist,
-            ...albumsAsCoverArtist,
-            ...albumsAsWallpaperArtist,
-            ...albumsAsBannerArtist,
-          ]),
-      },
-    ],
-
     albumsAsCommentator: reverseReferenceList({
       data: 'albumData',
       list: input.value('commentatorArtists'),
     }),
 
-    flashesAsContributor: reverseContributionList({
+    flashContributorContributions: reverseContributionList({
       data: 'flashData',
       list: input.value('contributorContribs'),
     }),
@@ -225,6 +134,8 @@ export class Artist extends Thing {
       data: 'flashData',
       list: input.value('commentatorArtists'),
     }),
+
+    totalDuration: artistTotalDuration(),
   });
 
   static [Thing.getSerializeDescriptors] = ({
@@ -240,18 +151,8 @@ export class Artist extends Thing {
 
     aliasNames: S.id,
 
-    tracksAsArtist: S.toRefs,
-    tracksAsContributor: S.toRefs,
-    tracksAsCoverArtist: S.toRefs,
     tracksAsCommentator: S.toRefs,
-
-    albumsAsAlbumArtist: S.toRefs,
-    albumsAsCoverArtist: S.toRefs,
-    albumsAsWallpaperArtist: S.toRefs,
-    albumsAsBannerArtist: S.toRefs,
     albumsAsCommentator: S.toRefs,
-
-    flashesAsContributor: S.toRefs,
   });
 
   static [Thing.findSpecs] = {
diff --git a/src/data/things/contribution.js b/src/data/things/contribution.js
new file mode 100644
index 00000000..79acf1e1
--- /dev/null
+++ b/src/data/things/contribution.js
@@ -0,0 +1,265 @@
+import {inspect} from 'node:util';
+
+import CacheableObject from '#cacheable-object';
+import {colors} from '#cli';
+import {input} from '#composite';
+import {empty} from '#sugar';
+import Thing from '#thing';
+import {isStringNonEmpty, isThing, validateReference} from '#validators';
+
+import {exitWithoutDependency, exposeDependency} from '#composite/control-flow';
+import {withNearbyItemFromList, withPropertyFromObject} from '#composite/data';
+import {withResolvedReference} from '#composite/wiki-data';
+import {flag, simpleDate} from '#composite/wiki-properties';
+
+import {
+  inheritFromContributionPresets,
+  thingPropertyMatches,
+  thingReferenceTypeMatches,
+  withContainingReverseContributionList,
+  withContributionArtist,
+  withContributionContext,
+  withMatchingContributionPresets,
+} from '#composite/things/contribution';
+
+export class Contribution extends Thing {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    thing: {
+      flags: {update: true, expose: true},
+      update: {validate: isThing},
+    },
+
+    thingProperty: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+
+    artistProperty: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+
+    date: simpleDate(),
+
+    artist: [
+      withContributionArtist({
+        ref: input.updateValue({
+          validate: validateReference('artist'),
+        }),
+      }),
+
+      exposeDependency({
+        dependency: '#artist',
+      }),
+    ],
+
+    annotation: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+
+    countInContributionTotals: [
+      inheritFromContributionPresets({
+        property: input.thisProperty(),
+      }),
+
+      flag(true),
+    ],
+
+    countInDurationTotals: [
+      inheritFromContributionPresets({
+        property: input.thisProperty(),
+      }),
+
+      flag(true),
+    ],
+
+    // Expose only
+
+    context: [
+      withContributionContext(),
+
+      {
+        dependencies: [
+          '#contributionTarget',
+          '#contributionProperty',
+        ],
+
+        compute: ({
+          ['#contributionTarget']: target,
+          ['#contributionProperty']: property,
+        }) => ({
+          target,
+          property,
+        }),
+      },
+    ],
+
+    matchingPresets: [
+      withMatchingContributionPresets(),
+
+      exposeDependency({
+        dependency: '#matchingContributionPresets',
+      }),
+    ],
+
+    // All the contributions from the list which includes this contribution.
+    // Note that this list contains not only other contributions by the same
+    // artist, but also this very contribution. It doesn't mix contributions
+    // exposed on different properties.
+    associatedContributions: [
+      exitWithoutDependency({
+        dependency: 'thing',
+        value: input.value([]),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'thingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'thingProperty',
+      }),
+
+      exposeDependency({
+        dependency: '#value',
+      }),
+    ],
+
+    isArtistContribution: thingPropertyMatches({
+      value: input.value('artistContribs'),
+    }),
+
+    isContributorContribution: thingPropertyMatches({
+      value: input.value('contributorContribs'),
+    }),
+
+    isCoverArtistContribution: thingPropertyMatches({
+      value: input.value('coverArtistContribs'),
+    }),
+
+    isBannerArtistContribution: thingPropertyMatches({
+      value: input.value('bannerArtistContribs'),
+    }),
+
+    isWallpaperArtistContribution: thingPropertyMatches({
+      value: input.value('wallpaperArtistContribs'),
+    }),
+
+    isForTrack: thingReferenceTypeMatches({
+      value: input.value('track'),
+    }),
+
+    isForAlbum: thingReferenceTypeMatches({
+      value: input.value('album'),
+    }),
+
+    isForFlash: thingReferenceTypeMatches({
+      value: input.value('flash'),
+    }),
+
+    previousBySameArtist: [
+      withContainingReverseContributionList().outputs({
+        '#containingReverseContributionList': '#list',
+      }),
+
+      exitWithoutDependency({
+        dependency: '#list',
+      }),
+
+      withNearbyItemFromList({
+        list: '#list',
+        item: input.myself(),
+        offset: input.value(-1),
+      }),
+
+      exposeDependency({
+        dependency: '#nearbyItem',
+      }),
+    ],
+
+    nextBySameArtist: [
+      withContainingReverseContributionList().outputs({
+        '#containingReverseContributionList': '#list',
+      }),
+
+      exitWithoutDependency({
+        dependency: '#list',
+      }),
+
+      withNearbyItemFromList({
+        list: '#list',
+        item: input.myself(),
+        offset: input.value(+1),
+      }),
+
+      exposeDependency({
+        dependency: '#nearbyItem',
+      }),
+    ],
+  });
+
+  [inspect.custom](depth, options, inspect) {
+    const parts = [];
+    const accentParts = [];
+
+    parts.push(Thing.prototype[inspect.custom].apply(this));
+
+    if (this.annotation) {
+      accentParts.push(colors.green(`"${this.annotation}"`));
+    }
+
+    if (this.date) {
+      accentParts.push(colors.yellow(this.date.toLocaleDateString()));
+    }
+
+    let artistRef;
+    if (depth >= 0) {
+      let artist;
+      try {
+        artist = this.artist;
+      } catch (_error) {
+        // Computing artist might crash for any reason - don't distract from
+        // other errors as a result of inspecting this contribution.
+      }
+
+      if (artist) {
+        artistRef =
+          colors.blue(Thing.getReference(artist));
+      }
+    } else {
+      artistRef =
+        colors.green(CacheableObject.getUpdateValue(this, 'artist'));
+    }
+
+    if (artistRef) {
+      accentParts.push(`by ${artistRef}`);
+    }
+
+    if (this.thing) {
+      if (depth >= 0) {
+        const newOptions = {
+          ...options,
+          depth:
+            (options.depth === null
+              ? null
+              : options.depth - 1),
+        };
+
+        accentParts.push(`to ${inspect(this.thing, newOptions)}`);
+      } else {
+        accentParts.push(`to ${colors.blue(Thing.getReference(this.thing))}`);
+      }
+    }
+
+    if (!empty(accentParts)) {
+      parts.push(` (${accentParts.join(', ')})`);
+    }
+
+    return parts.join('');
+  }
+}
diff --git a/src/data/things/flash.js b/src/data/things/flash.js
index ceed79f7..89e59fe7 100644
--- a/src/data/things/flash.js
+++ b/src/data/things/flash.js
@@ -7,7 +7,7 @@ import {sortFlashesChronologically} from '#sort';
 import Thing from '#thing';
 import {anyOf, isColor, isContentString, isDirectory, isNumber, isString}
   from '#validators';
-import {parseDate, parseContributors} from '#yaml';
+import {parseContributors, parseDate, parseDimensions} from '#yaml';
 
 import {withPropertyFromObject} from '#composite/data';
 
@@ -24,11 +24,13 @@ import {
   commentatorArtists,
   contentString,
   contributionList,
+  dimensions,
   directory,
   fileExtension,
   name,
   referenceList,
   simpleDate,
+  thing,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
@@ -39,7 +41,12 @@ import {withFlashSide} from '#composite/things/flash-act';
 export class Flash extends Thing {
   static [Thing.referenceType] = 'flash';
 
-  static [Thing.getPropertyDescriptors] = ({Artist, Track, FlashAct}) => ({
+  static [Thing.getPropertyDescriptors] = ({
+    Artist,
+    Track,
+    FlashAct,
+    WikiInfo,
+  }) => ({
     // Update & expose
 
     name: name('Unnamed Flash'),
@@ -89,7 +96,12 @@ export class Flash extends Thing {
 
     coverArtFileExtension: fileExtension('jpg'),
 
-    contributorContribs: contributionList(),
+    coverArtDimensions: dimensions(),
+
+    contributorContribs: contributionList({
+      date: 'date',
+      artistProperty: input.value('flashContributorContributions'),
+    }),
 
     featuredTracks: referenceList({
       class: input.value(Track),
@@ -115,6 +127,10 @@ export class Flash extends Thing {
       class: input.value(FlashAct),
     }),
 
+    wikiInfo: thing({
+      class: input.value(WikiInfo),
+    }),
+
     // Expose only
 
     commentatorArtists: commentatorArtists(),
@@ -171,6 +187,11 @@ export class Flash extends Thing {
 
       'Cover Art File Extension': {property: 'coverArtFileExtension'},
 
+      'Cover Art Dimensions': {
+        property: 'coverArtDimensions',
+        transform: parseDimensions,
+      },
+
       'Featured Tracks': {property: 'featuredTracks'},
 
       'Contributors': {
diff --git a/src/data/things/index.js b/src/data/things/index.js
index 4f87f492..f18e283a 100644
--- a/src/data/things/index.js
+++ b/src/data/things/index.js
@@ -11,6 +11,7 @@ import Thing from '#thing';
 import * as albumClasses from './album.js';
 import * as artTagClasses from './art-tag.js';
 import * as artistClasses from './artist.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';
@@ -24,6 +25,7 @@ const allClassLists = {
   'album.js': albumClasses,
   'art-tag.js': artTagClasses,
   'artist.js': artistClasses,
+  'contribution.js': contributionClasses,
   'flash.js': flashClasses,
   'group.js': groupClasses,
   'homepage-layout.js': homepageLayoutClasses,
diff --git a/src/data/things/language.js b/src/data/things/language.js
index dbe1ff3d..88f16ecb 100644
--- a/src/data/things/language.js
+++ b/src/data/things/language.js
@@ -127,6 +127,13 @@ export class Language extends Thing {
 
     // Expose only
 
+    onlyIfOptions: {
+      flags: {expose: true},
+      expose: {
+        compute: () => Symbol.for(`language.onlyIfOptions`),
+      },
+    },
+
     intl_date: this.#intlHelper(Intl.DateTimeFormat, {full: true}),
     intl_number: this.#intlHelper(Intl.NumberFormat),
     intl_listConjunction: this.#intlHelper(Intl.ListFormat, {type: 'conjunction'}),
@@ -201,9 +208,7 @@ export class Language extends Thing {
       args.at(-1) !== null;
 
     const key =
-      (hasOptions ? args.slice(0, -1) : args)
-        .filter(Boolean)
-        .join('.');
+      this.#joinKeyParts(hasOptions ? args.slice(0, -1) : args);
 
     const options =
       (hasOptions
@@ -218,18 +223,42 @@ export class Language extends Thing {
       throw new Error(`Invalid key ${key} accessed`);
     }
 
+    const constantCasify = name =>
+      name
+        .replace(/[A-Z]/g, '_$&')
+        .toUpperCase();
+
     // These will be filled up as we iterate over the template, slotting in
     // each option (if it's present).
     const missingOptionNames = new Set();
 
+    // These will also be filled. It's a bit different of an error, indicating
+    // a provided option was *expected,* but its value was null, undefined, or
+    // blank HTML content.
+    const valuelessOptionNames = new Set();
+
+    // These *might* be missing, and if they are, that's OK!! Instead of adding
+    // to the valueless set above, we'll just mark to return a blank for the
+    // whole string.
+    const expectedValuelessOptionNames =
+      new Set(
+        (options[this.onlyIfOptions] ?? [])
+          .map(constantCasify));
+
+    let seenExpectedValuelessOption = false;
+
+    const isValueless =
+      value =>
+        value === null ||
+        value === undefined ||
+        html.isBlank(value);
+
     // And this will have entries deleted as they're encountered in the
     // template. Leftover entries are misplaced.
     const optionsMap =
       new Map(
         Object.entries(options).map(([name, value]) => [
-          name
-            .replace(/[A-Z]/g, '_$&')
-            .toUpperCase(),
+          constantCasify(name),
           value,
         ]));
 
@@ -239,32 +268,48 @@ export class Language extends Thing {
       match: languageOptionRegex,
 
       insert: ({name: optionName}, canceledForming) => {
-        if (optionsMap.has(optionName)) {
-          let optionValue;
-
-          // We'll only need the option's value if we're going to use it as
-          // part of the formed output (see below).
-          if (!canceledForming) {
-            optionValue = optionsMap.get(optionName);
-          }
-
-          // But we always have to delete expected options off the provided
-          // option map, since the leftovers are what will be used to tell
-          // which are misplaced.
-          optionsMap.delete(optionName);
+        if (!optionsMap.has(optionName)) {
+          missingOptionNames.add(optionName);
 
-          if (canceledForming) {
-            return undefined;
-          } else {
-            return optionValue;
-          }
-        } else {
           // We don't need to continue forming the output if we've hit a
           // missing option name, since the end result of this formatString
           // call will be a thrown error, and formed output won't be needed.
-          missingOptionNames.add(optionName);
+          // Return undefined to mark canceledForming for the following
+          // iterations (and exit early out of this iteration).
+          return undefined;
+        }
+
+        // Even if we're not actually forming the output anymore, we'll still
+        // have to access this option's value to check if it is invalid.
+        const optionValue = optionsMap.get(optionName);
+
+        // We always have to delete expected options off the provided option
+        // map, since the leftovers are what will be used to tell which are
+        // misplaced - information you want even (or doubly so) if we've
+        // already stopped forming the output thanks to missing options.
+        optionsMap.delete(optionName);
+
+        // Just like if an option is missing, a valueless option cancels
+        // forming the rest of the output.
+        if (isValueless(optionValue)) {
+          // It's also an error, *except* if this option is one of the ones
+          // that we're indicated to *expect* might be valueless! In that case,
+          // we still need to stop forming the string (and mark a separate flag
+          // so that we return a blank), but it's not an error.
+          if (expectedValuelessOptionNames.has(optionName)) {
+            seenExpectedValuelessOption = true;
+          } else {
+            valuelessOptionNames.add(optionName);
+          }
+
           return undefined;
         }
+
+        if (canceledForming) {
+          return undefined;
+        }
+
+        return optionValue;
       },
     });
 
@@ -272,17 +317,30 @@ export class Language extends Thing {
       Array.from(optionsMap.keys());
 
     withAggregate({message: `Errors in options for string "${key}"`}, ({push}) => {
+      const names = set => Array.from(set).join(', ');
+
       if (!empty(missingOptionNames)) {
-        const names = Array.from(missingOptionNames).join(`, `);
-        push(new Error(`Missing options: ${names}`));
+        push(new Error(
+          `Missing options: ${names(missingOptionNames)}`));
+      }
+
+      if (!empty(valuelessOptionNames)) {
+        push(new Error(
+          `Valueless options: ${names(valuelessOptionNames)}`));
       }
 
       if (!empty(misplacedOptionNames)) {
-        const names = Array.from(misplacedOptionNames).join(`, `);
-        push(new Error(`Unexpected options: ${names}`));
+        push(new Error(
+          `Unexpected options: ${names(misplacedOptionNames)}`));
       }
     });
 
+    // If an option was valueless as marked to expect, then that indicates
+    // the whole string should be treated as blank content.
+    if (seenExpectedValuelessOption) {
+      return html.blank();
+    }
+
     return output;
   }
 
@@ -416,11 +474,32 @@ export class Language extends Thing {
   }
 
   formatDate(date) {
+    // Null or undefined date is blank content.
+    if (date === null || date === undefined) {
+      return html.blank();
+    }
+
     this.assertIntlAvailable('intl_date');
     return this.intl_date.format(date);
   }
 
   formatDateRange(startDate, endDate) {
+    // formatDateRange 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) {
+      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`);
+      }
+    }
+
     this.assertIntlAvailable('intl_date');
     return this.intl_date.formatRange(startDate, endDate);
   }
@@ -431,6 +510,17 @@ export class Language extends Thing {
     days: numDays = 0,
     approximate = false,
   }) {
+    // Give up if any of years, months, or days is null or undefined.
+    // These default to zero, so something's gone pretty badly wrong to
+    // pass in all or partial missing values.
+    if (
+      numYears === undefined || numYears === null ||
+      numMonths === undefined || numMonths === null ||
+      numDays === undefined || numDays === null
+    ) {
+      throw new Error(`Expected values or default zero for years, months, and days`);
+    }
+
     let basis;
 
     const years = this.countYears(numYears, {unit: true});
@@ -468,6 +558,14 @@ export class Language extends Thing {
     approximate = true,
     absolute = true,
   } = {}) {
+    // Give up if current and/or reference date is null or undefined.
+    if (
+      currentDate === undefined || currentDate === null ||
+      referenceDate === undefined || referenceDate === null
+    ) {
+      throw new Error(`Expected values for currentDate and referenceDate`);
+    }
+
     const currentInstant = toTemporalInstant.apply(currentDate);
     const referenceInstant = toTemporalInstant.apply(referenceDate);
 
@@ -528,6 +626,12 @@ export class Language extends Thing {
   }
 
   formatDuration(secTotal, {approximate = false, unit = false} = {}) {
+    // Null or undefined duration is blank content.
+    if (secTotal === null || secTotal === undefined) {
+      return html.blank();
+    }
+
+    // Zero duration is a "missing" string.
     if (secTotal === 0) {
       return this.formatString('count.duration.missing');
     }
@@ -565,6 +669,11 @@ export class Language extends Thing {
       throw new TypeError(`externalLinkSpec unavailable`);
     }
 
+    // Null or undefined url is blank content.
+    if (url === null || url === undefined) {
+      return html.blank();
+    }
+
     isExternalLinkContext(context);
 
     if (style === 'all') {
@@ -589,16 +698,31 @@ export class Language extends Thing {
   }
 
   formatIndex(value) {
+    // Null or undefined value is blank content.
+    if (value === null || value === undefined) {
+      return html.blank();
+    }
+
     this.assertIntlAvailable('intl_pluralOrdinal');
     return this.formatString('count.index.' + this.intl_pluralOrdinal.select(value), {index: value});
   }
 
   formatNumber(value) {
+    // Null or undefined value is blank content.
+    if (value === null || value === undefined) {
+      return html.blank();
+    }
+
     this.assertIntlAvailable('intl_number');
     return this.intl_number.format(value);
   }
 
   formatWordCount(value) {
+    // Null or undefined value is blank content.
+    if (value === null || value === undefined) {
+      return html.blank();
+    }
+
     const num = this.formatNumber(
       value > 1000 ? Math.floor(value / 100) / 10 : value
     );
@@ -612,6 +736,11 @@ export class Language extends Thing {
   }
 
   #formatListHelper(array, processFn) {
+    // Empty lists, null, and undefined are blank content.
+    if (empty(array) || array === null || array === undefined) {
+      return html.blank();
+    }
+
     // Operate on "insertion markers" instead of the actual contents of the
     // array, because the process function (likely an Intl operation) is taken
     // to only operate on strings. We'll insert the contents of the array back
@@ -673,10 +802,22 @@ export class Language extends Thing {
 
   // File sizes: 42.5 kB, 127.2 MB, 4.13 GB, 998.82 TB
   formatFileSize(bytes) {
-    if (!bytes) return '';
+    // Null or undefined bytes is blank content.
+    if (bytes === null || bytes === undefined) {
+      return html.blank();
+    }
+
+    // Zero bytes is blank content.
+    if (bytes === 0) {
+      return html.blank();
+    }
 
     bytes = parseInt(bytes);
-    if (isNaN(bytes)) return '';
+
+    // Non-number bytes is blank content! Wow.
+    if (isNaN(bytes)) {
+      return html.blank();
+    }
 
     const round = (exp) => Math.round(bytes / 10 ** (exp - 1)) / 10;
 
@@ -700,10 +841,42 @@ export class Language extends Thing {
       return this.formatString('count.fileSize.bytes', {bytes});
     }
   }
+
+  // Utility function to quickly provide a useful string key
+  // (generally a prefix) to stuff nested beneath it.
+  encapsulate(...args) {
+    const fn =
+      (typeof args.at(-1) === 'function'
+        ? args.at(-1)
+        : null);
+
+    const parts =
+      (fn
+        ? args.slice(0, -1)
+        : args);
+
+    const capsule =
+      this.#joinKeyParts(parts);
+
+    if (fn) {
+      return fn(capsule);
+    } else {
+      return capsule;
+    }
+  }
+
+  #joinKeyParts(parts) {
+    return parts.filter(Boolean).join('.');
+  }
 }
 
 const countHelper = (stringKey, optionName = stringKey) =>
   function(value, {unit = false} = {}) {
+    // Null or undefined value is blank content.
+    if (value === null || value === undefined) {
+      return html.blank();
+    }
+
     return this.formatString(
       unit
         ? `count.${stringKey}.withUnit.` + this.getUnitForm(value)
diff --git a/src/data/things/track.js b/src/data/things/track.js
index 725b1bb7..4aaf364c 100644
--- a/src/data/things/track.js
+++ b/src/data/things/track.js
@@ -18,7 +18,6 @@ import {
 } from '#yaml';
 
 import {withPropertyFromObject} from '#composite/data';
-import {withResolvedContribs} from '#composite/wiki-data';
 
 import {
   exitWithoutDependency,
@@ -26,9 +25,16 @@ import {
   exposeDependency,
   exposeDependencyOrContinue,
   exposeUpdateValueOrContinue,
+  exposeWhetherDependencyAvailable,
 } from '#composite/control-flow';
 
 import {
+  withRecontextualizedContributionList,
+  withRedatedContributionList,
+  withResolvedContribs,
+} from '#composite/wiki-data';
+
+import {
   additionalFiles,
   additionalNameList,
   commentary,
@@ -43,8 +49,9 @@ import {
   referenceList,
   reverseReferenceList,
   simpleDate,
-  singleReference,
   simpleString,
+  singleReference,
+  thing,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
@@ -52,21 +59,31 @@ import {
 import {
   exitWithoutUniqueCoverArt,
   inferredAdditionalNameList,
+  inheritContributionListFromOriginalRelease,
   inheritFromOriginalRelease,
   sharedAdditionalNameList,
   trackReverseReferenceList,
   withAlbum,
   withAlwaysReferenceByDirectory,
   withContainingTrackSection,
+  withDate,
   withHasUniqueCoverArt,
+  withOriginalRelease,
   withOtherReleases,
   withPropertyFromAlbum,
+  withTrackArtDate,
 } from '#composite/things/track';
 
 export class Track extends Thing {
   static [Thing.referenceType] = 'track';
 
-  static [Thing.getPropertyDescriptors] = ({Album, ArtTag, Artist, Flash}) => ({
+  static [Thing.getPropertyDescriptors] = ({
+    Album,
+    ArtTag,
+    Artist,
+    Flash,
+    WikiInfo,
+  }) => ({
     // Update & expose
 
     name: name('Unnamed Track'),
@@ -137,27 +154,14 @@ export class Track extends Thing {
       }),
     ],
 
-    // Date of cover art release. Like coverArtFileExtension, this represents
-    // only the track's own unique cover artwork, if any. This exposes only as
-    // the track's own coverArtDate or its album's trackArtDate, so if neither
-    // is specified, this value is null.
     coverArtDate: [
-      withHasUniqueCoverArt(),
-
-      exitWithoutDependency({
-        dependency: '#hasUniqueCoverArt',
-        mode: input.value('falsy'),
-      }),
-
-      exposeUpdateValueOrContinue({
-        validate: input.value(isDate),
-      }),
-
-      withPropertyFromAlbum({
-        property: input.value('trackArtDate'),
+      withTrackArtDate({
+        from: input.updateValue({
+          validate: isDate,
+        }),
       }),
 
-      exposeDependency({dependency: '#album.trackArtDate'}),
+      exposeDependency({dependency: '#trackArtDate'}),
     ],
 
     coverArtDimensions: [
@@ -192,12 +196,15 @@ export class Track extends Thing {
     }),
 
     artistContribs: [
-      inheritFromOriginalRelease({
-        notFoundValue: input.value([]),
-      }),
+      inheritContributionListFromOriginalRelease(),
+
+      withDate(),
 
       withResolvedContribs({
         from: input.updateValue({validate: isContributionList}),
+        thingProperty: input.thisProperty(),
+        artistProperty: input.value('trackArtistContributions'),
+        date: '#date',
       }).outputs({
         '#resolvedContribs': '#artistContribs',
       }),
@@ -211,15 +218,28 @@ export class Track extends Thing {
         property: input.value('artistContribs'),
       }),
 
+      withRecontextualizedContributionList({
+        list: '#album.artistContribs',
+        artistProperty: input.value('trackArtistContributions'),
+      }),
+
+      withRedatedContributionList({
+        list: '#album.artistContribs',
+        date: '#date',
+      }),
+
       exposeDependency({dependency: '#album.artistContribs'}),
     ],
 
     contributorContribs: [
-      inheritFromOriginalRelease({
-        notFoundValue: input.value([]),
-      }),
+      inheritContributionListFromOriginalRelease(),
 
-      contributionList(),
+      withDate(),
+
+      contributionList({
+        date: '#date',
+        artistProperty: input.value('trackContributorContributions'),
+      }),
     ],
 
     // Cover artists aren't inherited from the original release, since it
@@ -230,8 +250,15 @@ export class Track extends Thing {
         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',
       }),
@@ -245,6 +272,16 @@ export class Track extends Thing {
         property: input.value('trackCoverArtistContribs'),
       }),
 
+      withRecontextualizedContributionList({
+        list: '#album.trackCoverArtistContribs',
+        artistProperty: input.value('trackCoverArtistContributions'),
+      }),
+
+      withRedatedContributionList({
+        list: '#album.trackCoverArtistContribs',
+        date: '#trackArtDate',
+      }),
+
       exposeDependency({dependency: '#album.trackCoverArtistContribs'}),
     ],
 
@@ -306,6 +343,10 @@ export class Track extends Thing {
       class: input.value(Track),
     }),
 
+    wikiInfo: thing({
+      class: input.value(WikiInfo),
+    }),
+
     // Expose only
 
     commentatorArtists: commentatorArtists(),
@@ -316,13 +357,8 @@ export class Track extends Thing {
     ],
 
     date: [
-      exposeDependencyOrContinue({dependency: 'dateFirstReleased'}),
-
-      withPropertyFromAlbum({
-        property: input.value('date'),
-      }),
-
-      exposeDependency({dependency: '#album.date'}),
+      withDate(),
+      exposeDependency({dependency: '#date'}),
     ],
 
     hasUniqueCoverArt: [
@@ -330,6 +366,23 @@ export class Track extends Thing {
       exposeDependency({dependency: '#hasUniqueCoverArt'}),
     ],
 
+    isOriginalRelease: [
+      withOriginalRelease(),
+
+      exposeWhetherDependencyAvailable({
+        dependency: '#originalRelease',
+        negate: input.value(true),
+      }),
+    ],
+
+    isRerelease: [
+      withOriginalRelease(),
+
+      exposeWhetherDependencyAvailable({
+        dependency: '#originalRelease',
+      }),
+    ],
+
     otherReleases: [
       withOtherReleases(),
       exposeDependency({dependency: '#otherReleases'}),
diff --git a/src/data/things/wiki-info.js b/src/data/things/wiki-info.js
index 316bd3bb..b7b7b01c 100644
--- a/src/data/things/wiki-info.js
+++ b/src/data/things/wiki-info.js
@@ -3,8 +3,18 @@ export const WIKI_INFO_FILE = 'wiki-info.yaml';
 import {input} from '#composite';
 import find from '#find';
 import Thing from '#thing';
-import {isColor, isLanguageCode, isName, isURL} from '#validators';
-
+import {parseContributionPresets} from '#yaml';
+
+import {
+  isBoolean,
+  isColor,
+  isContributionPresetList,
+  isLanguageCode,
+  isName,
+  isURL,
+} from '#validators';
+
+import {exitWithoutDependency} from '#composite/control-flow';
 import {contentString, flag, name, referenceList, wikiData}
   from '#composite/wiki-properties';
 
@@ -57,6 +67,11 @@ export class WikiInfo extends Thing {
       data: 'groupData',
     }),
 
+    contributionPresets: {
+      flags: {update: true, expose: true},
+      update: {validate: isContributionPresetList},
+    },
+
     // Feature toggles
     enableFlashesAndGames: flag(false),
     enableListings: flag(false),
@@ -64,8 +79,26 @@ export class WikiInfo extends Thing {
     enableArtTagUI: flag(false),
     enableGroupUI: flag(false),
 
+    enableSearch: [
+      exitWithoutDependency({
+        dependency: 'searchDataAvailable',
+        mode: input.value('falsy'),
+        value: input.value(false),
+      }),
+
+      flag(true),
+    ],
+
     // Update only
 
+    searchDataAvailable: {
+      flags: {update: true},
+      update: {
+        validate: isBoolean,
+        default: false,
+      },
+    },
+
     groupData: wikiData({
       class: input.value(Group),
     }),
@@ -86,6 +119,11 @@ export class WikiInfo extends Thing {
       'Enable News': {property: 'enableNews'},
       'Enable Art Tag UI': {property: 'enableArtTagUI'},
       'Enable Group UI': {property: 'enableGroupUI'},
+
+      'Contribution Presets': {
+        property: 'contributionPresets',
+        transform: parseContributionPresets,
+      },
     },
   };
 
diff --git a/src/data/validators.js b/src/data/validators.js
index 5d681311..354de6fa 100644
--- a/src/data/validators.js
+++ b/src/data/validators.js
@@ -636,10 +636,65 @@ export function isThing(thing) {
 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),
diff --git a/src/data/yaml.js b/src/data/yaml.js
index c9ce5329..7a16341b 100644
--- a/src/data/yaml.js
+++ b/src/data/yaml.js
@@ -370,34 +370,42 @@ export function parseDuration(string) {
   }
 }
 
-export function parseAdditionalFiles(array) {
-  if (!Array.isArray(array)) {
-    // Error will be caught when validating against whatever this value is
-    return array;
-  }
-
-  return array.map((item) => ({
-    title: item['Title'],
-    description: item['Description'] ?? null,
-    files: item['Files'],
-  }));
-}
-
 export const extractAccentRegex =
   /^(?<main>.*?)(?: \((?<accent>.*)\))?$/;
 
 export const extractPrefixAccentRegex =
   /^(?:\((?<accent>.*)\) )?(?<main>.*?)$/;
 
-export function parseContributors(contributionStrings) {
+// TODO: Should this fit better within actual YAML loading infrastructure??
+export function parseArrayEntries(entries, mapFn) {
   // If this isn't something we can parse, just return it as-is.
   // The Thing object's validators will handle the data error better
   // than we're able to here.
-  if (!Array.isArray(contributionStrings)) {
-    return contributionStrings;
+  if (!Array.isArray(entries)) {
+    return entries;
+  }
+
+  // If the array is REALLY ACTUALLY empty (it's represented in YAML
+  // as literally an empty []), that's something we want to reflect.
+  if (empty(entries)) {
+    return entries;
   }
 
-  return contributionStrings.map(item => {
+  const nonNullEntries =
+    entries.filter(value => value !== null);
+
+  // On the other hand, if the array only contains null, it's just
+  // a placeholder, so skip over the field like it's not actually
+  // been put there yet.
+  if (empty(nonNullEntries)) {
+    return null;
+  }
+
+  return entries.map(mapFn);
+}
+
+export function parseContributors(entries) {
+  return parseArrayEntries(entries, item => {
     if (typeof item === 'object' && item['Who'])
       return {
         artist: item['Who'],
@@ -408,6 +416,9 @@ export function parseContributors(contributionStrings) {
       return {
         artist: item['Artist'],
         annotation: item['Annotation'] ?? null,
+
+        countInContributionTotals: item['Count In Contribution Totals'] ?? null,
+        countInDurationTotals: item['Count In Duration Totals'] ?? null,
       };
 
     if (typeof item !== 'string') return item;
@@ -422,12 +433,20 @@ export function parseContributors(contributionStrings) {
   });
 }
 
-export function parseAdditionalNames(additionalNameStrings) {
-  if (!Array.isArray(additionalNameStrings)) {
-    return additionalNameStrings;
-  }
+export function parseAdditionalFiles(entries) {
+  return parseArrayEntries(entries, item => {
+    if (typeof item !== 'object') return item;
 
-  return additionalNameStrings.map(item => {
+    return {
+      title: item['Title'],
+      description: item['Description'] ?? null,
+      files: item['Files'],
+    };
+  });
+}
+
+export function parseAdditionalNames(entries) {
+  return parseArrayEntries(entries, item => {
     if (typeof item === 'object' && item['Name'])
       return {name: item['Name'], annotation: item['Annotation'] ?? null};
 
@@ -466,6 +485,73 @@ export function parseDimensions(string) {
   return nums;
 }
 
+export const contributionPresetYAMLSpec = [
+  {from: 'Album', to: 'album', fields: [
+    {from: 'Artists', to: 'artistContribs'},
+  ]},
+
+  {from: 'Flash', to: 'flash', fields: [
+    {from: 'Contributors', to: 'contributorContribs'},
+  ]},
+
+  {from: 'Track', to: 'track', fields: [
+    {from: 'Artists', to: 'artistContribs'},
+    {from: 'Contributors', to: 'contributorContribs'},
+  ]},
+];
+
+export function parseContributionPresetContext(context) {
+  if (!Array.isArray(context)) {
+    return context;
+  }
+
+  const [target, ...fields] = context;
+
+  const targetEntry =
+    contributionPresetYAMLSpec
+      .find(({from}) => from === target);
+
+  if (!targetEntry) {
+    return context;
+  }
+
+  const properties =
+    fields.map(field => {
+      const fieldEntry =
+        targetEntry.fields
+          .find(({from}) => from === field);
+
+      if (!fieldEntry) return field;
+
+      return fieldEntry.to;
+    });
+
+  return [targetEntry.to, ...properties];
+}
+
+export function parseContributionPresets(list) {
+  if (!Array.isArray(list)) return list;
+
+  return list.map(item => {
+    if (typeof item !== 'object') return item;
+
+    return {
+      annotation:
+        item['Annotation'] ?? null,
+
+      context:
+        parseContributionPresetContext(
+          item['Context'] ?? null),
+
+      countInContributionTotals:
+        item['Count In Contribution Totals'] ?? null,
+
+      countInDurationTotals:
+        item['Count In Duration Totals'] ?? null,
+    };
+  });
+}
+
 // documentModes: Symbols indicating sets of behavior for loading and processing
 // data files.
 export const documentModes = {
@@ -1066,6 +1152,7 @@ export function linkWikiDataArrays(wikiData) {
       'artTagData',
       'artistData',
       'groupData',
+      'wikiInfo',
     ]],
 
     [wikiData.artTagData, [
@@ -1084,6 +1171,7 @@ export function linkWikiDataArrays(wikiData) {
       'artistData',
       'flashActData',
       'trackData',
+      'wikiInfo',
     ]],
 
     [wikiData.flashActData, [
@@ -1115,6 +1203,7 @@ export function linkWikiDataArrays(wikiData) {
       'artistData',
       'flashData',
       'trackData',
+      'wikiInfo',
     ]],
 
     [[wikiData.wikiInfo], [