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hsmusic-wiki - HSMusic - static wiki software cataloguing collaborative creation
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-rw-r--r--src/data/things/album.js677
-rw-r--r--src/data/things/art-tag.js125
-rw-r--r--src/data/things/artist.js228
-rw-r--r--src/data/things/artwork.js399
-rw-r--r--src/data/things/contribution.js302
-rw-r--r--src/data/things/flash.js142
-rw-r--r--src/data/things/group.js98
-rw-r--r--src/data/things/homepage-layout.js313
-rw-r--r--src/data/things/index.js45
-rw-r--r--src/data/things/language.js251
-rw-r--r--src/data/things/sorting-rule.js386
-rw-r--r--src/data/things/static-page.js9
-rw-r--r--src/data/things/track.js467
-rw-r--r--src/data/things/wiki-info.js60
14 files changed, 2907 insertions, 595 deletions
diff --git a/src/data/things/album.js b/src/data/things/album.js
index 40cd4631..4c85ddfa 100644
--- a/src/data/things/album.js
+++ b/src/data/things/album.js
@@ -1,26 +1,43 @@
 export const DATA_ALBUM_DIRECTORY = 'album';
 
 import * as path from 'node:path';
+import {inspect} from 'node:util';
 
+import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import {traverse} from '#node-utils';
 import {sortAlbumsTracksChronologically, sortChronologically} from '#sort';
-import {empty} from '#sugar';
+import {accumulateSum, empty} from '#sugar';
 import Thing from '#thing';
-import {isDate} from '#validators';
-import {parseAdditionalFiles, parseContributors, parseDate, parseDimensions}
-  from '#yaml';
+import {isColor, isDate, isDirectory, isNumber} from '#validators';
 
-import {exposeDependency, exposeUpdateValueOrContinue}
+import {
+  parseAdditionalFiles,
+  parseAdditionalNames,
+  parseAnnotatedReferences,
+  parseArtwork,
+  parseContributors,
+  parseDate,
+  parseDimensions,
+  parseWallpaperParts,
+} from '#yaml';
+
+import {exitWithoutDependency, exposeDependency, exposeUpdateValueOrContinue}
   from '#composite/control-flow';
-import {exitWithoutContribs} from '#composite/wiki-data';
+import {withPropertyFromObject} from '#composite/data';
+
+import {exitWithoutContribs, withDirectory, withCoverArtDate}
+  from '#composite/wiki-data';
 
 import {
   additionalFiles,
+  additionalNameList,
   commentary,
   color,
   commentatorArtists,
+  constitutibleArtwork,
+  constitutibleArtworkList,
+  contentString,
   contribsPresent,
   contributionList,
   dimensions,
@@ -28,26 +45,61 @@ import {
   fileExtension,
   flag,
   name,
+  referencedArtworkList,
   referenceList,
+  reverseReferenceList,
   simpleDate,
   simpleString,
+  soupyFind,
+  soupyReverse,
+  thing,
+  thingList,
   urls,
+  wallpaperParts,
   wikiData,
 } from '#composite/wiki-properties';
 
-import {withTracks, withTrackSections} from '#composite/things/album';
+import {withHasCoverArt, withTracks} from '#composite/things/album';
+import {withAlbum, withContinueCountingFrom, withStartCountingFrom}
+  from '#composite/things/track-section';
 
 export class Album extends Thing {
   static [Thing.referenceType] = 'album';
 
-  static [Thing.getPropertyDescriptors] = ({ArtTag, Artist, Group, Track}) => ({
+  static [Thing.getPropertyDescriptors] = ({
+    ArtTag,
+    Artwork,
+    Group,
+    Track,
+    TrackSection,
+    WikiInfo,
+  }) => ({
     // Update & expose
 
     name: name('Unnamed Album'),
-    color: color(),
     directory: directory(),
+
+    directorySuffix: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(isDirectory),
+      }),
+
+      withDirectory(),
+
+      exposeDependency({
+        dependency: '#directory',
+      }),
+    ],
+
+    alwaysReferenceByDirectory: flag(false),
+    alwaysReferenceTracksByDirectory: flag(false),
+    suffixTrackDirectories: flag(false),
+
+    color: color(),
     urls: urls(),
 
+    additionalNames: additionalNameList(),
+
     bandcampAlbumIdentifier: simpleString(),
     bandcampArtworkIdentifier: simpleString(),
 
@@ -56,13 +108,13 @@ export class Album extends Thing {
     dateAddedToWiki: simpleDate(),
 
     coverArtDate: [
-      exitWithoutContribs({contribs: 'coverArtistContribs'}),
-
-      exposeUpdateValueOrContinue({
-        validate: input.value(isDate),
+      withCoverArtDate({
+        from: input.updateValue({
+          validate: isDate,
+        }),
       }),
 
-      exposeDependency({dependency: 'date'}),
+      exposeDependency({dependency: '#coverArtDate'}),
     ],
 
     coverArtFileExtension: [
@@ -87,6 +139,15 @@ export class Album extends Thing {
       simpleString(),
     ],
 
+    wallpaperParts: [
+      exitWithoutContribs({
+        contribs: 'wallpaperArtistContribs',
+        value: input.value([]),
+      }),
+
+      wallpaperParts(),
+    ],
+
     bannerStyle: [
       exitWithoutContribs({contribs: 'bannerArtistContribs'}),
       simpleString(),
@@ -97,33 +158,105 @@ export class Album extends Thing {
       dimensions(),
     ],
 
+    trackDimensions: dimensions(),
+
     bannerDimensions: [
       exitWithoutContribs({contribs: 'bannerArtistContribs'}),
       dimensions(),
     ],
 
+    wallpaperArtwork: [
+      exitWithoutDependency({
+        dependency: 'wallpaperArtistContribs',
+        mode: input.value('empty'),
+        value: input.value(null),
+      }),
+
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Wallpaper Artwork'),
+    ],
+
+    bannerArtwork: [
+      exitWithoutDependency({
+        dependency: 'bannerArtistContribs',
+        mode: input.value('empty'),
+        value: input.value(null),
+      }),
+
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Banner Artwork'),
+    ],
+
+    coverArtworks: [
+      withHasCoverArt(),
+
+      exitWithoutDependency({
+        dependency: '#hasCoverArt',
+        mode: input.value('falsy'),
+        value: input.value([]),
+      }),
+
+      constitutibleArtworkList.fromYAMLFieldSpec
+        .call(this, 'Cover Artwork'),
+    ],
+
     hasTrackNumbers: flag(true),
     isListedOnHomepage: flag(true),
     isListedInGalleries: flag(true),
 
     commentary: commentary(),
+    creditSources: commentary(),
     additionalFiles: additionalFiles(),
 
-    trackSections: [
-      withTrackSections(),
-      exposeDependency({dependency: '#trackSections'}),
+    trackSections: thingList({
+      class: input.value(TrackSection),
+    }),
+
+    artistContribs: contributionList({
+      date: 'date',
+      artistProperty: input.value('albumArtistContributions'),
+    }),
+
+    coverArtistContribs: [
+      withCoverArtDate(),
+
+      contributionList({
+        date: '#coverArtDate',
+        artistProperty: input.value('albumCoverArtistContributions'),
+      }),
     ],
 
-    artistContribs: contributionList(),
-    coverArtistContribs: contributionList(),
-    trackCoverArtistContribs: contributionList(),
-    wallpaperArtistContribs: contributionList(),
-    bannerArtistContribs: contributionList(),
+    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(),
+
+      contributionList({
+        date: '#coverArtDate',
+        artistProperty: input.value('albumWallpaperArtistContributions'),
+      }),
+    ],
+
+    bannerArtistContribs: [
+      withCoverArtDate(),
+
+      contributionList({
+        date: '#coverArtDate',
+        artistProperty: input.value('albumBannerArtistContributions'),
+      }),
+    ],
 
     groups: referenceList({
       class: input.value(Group),
-      find: input.value(find.group),
-      data: 'groupData',
+      find: soupyFind.input('group'),
     }),
 
     artTags: [
@@ -134,37 +267,43 @@ export class Album extends Thing {
 
       referenceList({
         class: input.value(ArtTag),
-        find: input.value(find.artTag),
-        data: 'artTagData',
+        find: soupyFind.input('artTag'),
       }),
     ],
 
-    // Update only
+    referencedArtworks: [
+      exitWithoutContribs({
+        contribs: 'coverArtistContribs',
+        value: input.value([]),
+      }),
 
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
+      referencedArtworkList(),
+    ],
 
-    artTagData: wikiData({
-      class: input.value(ArtTag),
-    }),
+    // Update only
 
-    groupData: wikiData({
-      class: input.value(Group),
+    find: soupyFind(),
+    reverse: soupyReverse(),
+
+    // used for referencedArtworkList (mixedFind)
+    artworkData: wikiData({
+      class: input.value(Artwork),
     }),
 
-    // Only the tracks which belong to this album.
-    // Necessary for computing the track list, so provide this statically
-    // or keep it updated.
-    ownTrackData: wikiData({
-      class: input.value(Track),
+    // used for withMatchingContributionPresets (indirectly by Contribution)
+    wikiInfo: thing({
+      class: input.value(WikiInfo),
     }),
 
     // Expose only
 
     commentatorArtists: commentatorArtists(),
 
-    hasCoverArt: contribsPresent({contribs: 'coverArtistContribs'}),
+    hasCoverArt: [
+      withHasCoverArt(),
+      exposeDependency({dependency: '#hasCoverArt'}),
+    ],
+
     hasWallpaperArt: contribsPresent({contribs: 'wallpaperArtistContribs'}),
     hasBannerArt: contribsPresent({contribs: 'bannerArtistContribs'}),
 
@@ -216,15 +355,130 @@ export class Album extends Thing {
 
   static [Thing.findSpecs] = {
     album: {
-      referenceTypes: ['album', 'album-commentary', 'album-gallery'],
+      referenceTypes: [
+        'album',
+        'album-commentary',
+        'album-gallery',
+      ],
+
+      bindTo: 'albumData',
+
+      getMatchableNames: album =>
+        (album.alwaysReferenceByDirectory 
+          ? [] 
+          : [album.name]),
+    },
+
+    albumWithArtwork: {
+      referenceTypes: [
+        'album',
+        'album-referencing-artworks',
+        'album-referenced-artworks',
+      ],
+
+      bindTo: 'albumData',
+
+      include: album =>
+        album.hasCoverArt,
+
+      getMatchableNames: album =>
+        (album.alwaysReferenceByDirectory 
+          ? [] 
+          : [album.name]),
+    },
+
+    albumPrimaryArtwork: {
+      [Thing.findThisThingOnly]: false,
+
+      referenceTypes: [
+        'album',
+        'album-referencing-artworks',
+        'album-referenced-artworks',
+      ],
+
+      bindTo: 'artworkData',
+
+      include: (artwork, {Artwork, Album}) =>
+        artwork instanceof Artwork &&
+        artwork.thing instanceof Album &&
+        artwork === artwork.thing.coverArtworks[0],
+
+      getMatchableNames: ({thing: album}) =>
+        (album.alwaysReferenceByDirectory
+          ? []
+          : [album.name]),
+
+      getMatchableDirectories: ({thing: album}) =>
+        [album.directory],
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    albumsWhoseTracksInclude: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.tracks,
+    },
+
+    albumsWhoseTrackSectionsInclude: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.trackSections,
+    },
+
+    albumsWhoseArtworksFeature: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.artTags,
+    },
+
+    albumsWhoseGroupsInclude: {
+      bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.groups,
+    },
+
+    albumArtistContributionsBy:
+      soupyReverse.contributionsBy('albumData', 'artistContribs'),
+
+    albumCoverArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('albumData', 'coverArtworks'),
+
+    albumWallpaperArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('albumData', 'wallpaperArtwork', {single: true}),
+
+    albumBannerArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('albumData', 'bannerArtwork', {single: true}),
+
+    albumsWithCommentaryBy: {
       bindTo: 'albumData',
+
+      referencing: album => [album],
+      referenced: album => album.commentatorArtists,
     },
   };
 
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Album': {property: 'name'},
+
       'Directory': {property: 'directory'},
+      'Directory Suffix': {property: 'directorySuffix'},
+      'Suffix Track Directories': {property: 'suffixTrackDirectories'},
+
+      'Always Reference By Directory': {property: 'alwaysReferenceByDirectory'},
+      'Always Reference Tracks By Directory': {
+        property: 'alwaysReferenceTracksByDirectory',
+      },
+
+      'Additional Names': {
+        property: 'additionalNames',
+        transform: parseAdditionalNames,
+      },
 
       'Bandcamp Album ID': {
         property: 'bandcampAlbumIdentifier',
@@ -248,6 +502,46 @@ export class Album extends Thing {
       'Listed on Homepage': {property: 'isListedOnHomepage'},
       'Listed in Galleries': {property: 'isListedInGalleries'},
 
+      'Cover Artwork': {
+        property: 'coverArtworks',
+        transform:
+          parseArtwork({
+            dimensionsFromThingProperty: 'coverArtDimensions',
+            fileExtensionFromThingProperty: 'coverArtFileExtension',
+            dateFromThingProperty: 'coverArtDate',
+            artistContribsFromThingProperty: 'coverArtistContribs',
+            artistContribsArtistProperty: 'albumCoverArtistContributions',
+            artTagsFromThingProperty: 'artTags',
+            referencedArtworksFromThingProperty: 'referencedArtworks',
+          }),
+      },
+
+      'Banner Artwork': {
+        property: 'bannerArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            dimensionsFromThingProperty: 'bannerDimensions',
+            fileExtensionFromThingProperty: 'bannerFileExtension',
+            dateFromThingProperty: 'date',
+            artistContribsFromThingProperty: 'bannerArtistContribs',
+            artistContribsArtistProperty: 'albumBannerArtistContributions',
+          }),
+      },
+
+      'Wallpaper Artwork': {
+        property: 'wallpaperArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            dimensionsFromThingProperty: null,
+            fileExtensionFromThingProperty: 'wallpaperFileExtension',
+            dateFromThingProperty: 'date',
+            artistContribsFromThingProperty: 'wallpaperArtistContribs',
+            artistContribsArtistProperty: 'albumWallpaperArtistContributions',
+          }),
+      },
+
       'Cover Art Date': {
         property: 'coverArtDate',
         transform: parseDate,
@@ -271,6 +565,11 @@ export class Album extends Thing {
         transform: parseDimensions,
       },
 
+      'Default Track Dimensions': {
+        property: 'trackDimensions',
+        transform: parseDimensions,
+      },
+
       'Wallpaper Artists': {
         property: 'wallpaperArtistContribs',
         transform: parseContributors,
@@ -279,6 +578,11 @@ export class Album extends Thing {
       'Wallpaper Style': {property: 'wallpaperStyle'},
       'Wallpaper File Extension': {property: 'wallpaperFileExtension'},
 
+      'Wallpaper Parts': {
+        property: 'wallpaperParts',
+        transform: parseWallpaperParts,
+      },
+
       'Banner Artists': {
         property: 'bannerArtistContribs',
         transform: parseContributors,
@@ -293,12 +597,18 @@ export class Album extends Thing {
       },
 
       'Commentary': {property: 'commentary'},
+      'Credit Sources': {property: 'creditSources'},
 
       'Additional Files': {
         property: 'additionalFiles',
         transform: parseAdditionalFiles,
       },
 
+      'Referenced Artworks': {
+        property: 'referencedArtworks',
+        transform: parseAnnotatedReferences,
+      },
+
       'Franchises': {ignore: true},
 
       'Artists': {
@@ -321,11 +631,23 @@ export class Album extends Thing {
 
       'Review Points': {ignore: true},
     },
+
+    invalidFieldCombinations: [
+      {message: `Specify one wallpaper style or multiple wallpaper parts, not both`, fields: [
+        'Wallpaper Parts',
+        'Wallpaper Style',
+      ]},
+
+      {message: `Wallpaper file extensions are specified on asset, per part`, fields: [
+        'Wallpaper Parts',
+        'Wallpaper File Extension',
+      ]},
+    ],
   };
 
   static [Thing.getYamlLoadingSpec] = ({
     documentModes: {headerAndEntries},
-    thingConstructors: {Album, Track, TrackSectionHelper},
+    thingConstructors: {Album, Track},
   }) => ({
     title: `Process album files`,
 
@@ -339,68 +661,85 @@ export class Album extends Thing {
     headerDocumentThing: Album,
     entryDocumentThing: document =>
       ('Section' in document
-        ? TrackSectionHelper
+        ? TrackSection
         : Track),
 
     save(results) {
       const albumData = [];
+      const trackSectionData = [];
       const trackData = [];
+      const artworkData = [];
 
       for (const {header: album, entries} of results) {
-        // We can't mutate an array once it's set as a property value,
-        // so prepare the track sections that will show up in a track list
-        // all the way before actually applying them. (It's okay to mutate
-        // an individual section before applying it, since those are just
-        // generic objects; they aren't Things in and of themselves.)
         const trackSections = [];
-        const ownTrackData = [];
 
-        let currentTrackSection = {
+        let currentTrackSection = new TrackSection();
+        let currentTrackSectionTracks = [];
+
+        Object.assign(currentTrackSection, {
           name: `Default Track Section`,
           isDefaultTrackSection: true,
-          tracks: [],
-        };
+        });
 
         const albumRef = Thing.getReference(album);
 
         const closeCurrentTrackSection = () => {
-          if (!empty(currentTrackSection.tracks)) {
-            trackSections.push(currentTrackSection);
+          if (
+            currentTrackSection.isDefaultTrackSection &&
+            empty(currentTrackSectionTracks)
+          ) {
+            return;
           }
+
+          currentTrackSection.tracks =
+            currentTrackSectionTracks;
+
+          trackSections.push(currentTrackSection);
+          trackSectionData.push(currentTrackSection);
         };
 
         for (const entry of entries) {
-          if (entry instanceof TrackSectionHelper) {
+          if (entry instanceof TrackSection) {
             closeCurrentTrackSection();
-
-            currentTrackSection = {
-              name: entry.name,
-              color: entry.color,
-              dateOriginallyReleased: entry.dateOriginallyReleased,
-              isDefaultTrackSection: false,
-              tracks: [],
-            };
-
+            currentTrackSection = entry;
+            currentTrackSectionTracks = [];
             continue;
           }
 
+          currentTrackSectionTracks.push(entry);
           trackData.push(entry);
 
-          entry.dataSourceAlbum = albumRef;
+          // Set the track's album before accessing its list of artworks.
+          // The existence of its artwork objects may depend on access to
+          // its album's 'Default Track Cover Artists'.
+          entry.album = album;
 
-          ownTrackData.push(entry);
-          currentTrackSection.tracks.push(Thing.getReference(entry));
+          artworkData.push(...entry.trackArtworks);
         }
 
         closeCurrentTrackSection();
 
         albumData.push(album);
 
+        artworkData.push(...album.coverArtworks);
+
+        if (album.bannerArtwork) {
+          artworkData.push(album.bannerArtwork);
+        }
+
+        if (album.wallpaperArtwork) {
+          artworkData.push(album.wallpaperArtwork);
+        }
+
         album.trackSections = trackSections;
-        album.ownTrackData = ownTrackData;
       }
 
-      return {albumData, trackData};
+      return {
+        albumData,
+        trackSectionData,
+        trackData,
+        artworkData,
+      };
     },
 
     sort({albumData, trackData}) {
@@ -408,27 +747,213 @@ export class Album extends Thing {
       sortAlbumsTracksChronologically(trackData);
     },
   });
+
+  getOwnArtworkPath(artwork) {
+    if (artwork === this.bannerArtwork) {
+      return [
+        'media.albumBanner',
+        this.directory,
+        artwork.fileExtension,
+      ];
+    }
+
+    if (artwork === this.wallpaperArtwork) {
+      if (!empty(this.wallpaperParts)) {
+        return null;
+      }
+
+      return [
+        'media.albumWallpaper',
+        this.directory,
+        artwork.fileExtension,
+      ];
+    }
+
+    // TODO: using trackCover here is obviously, badly wrong
+    // but we ought to refactor banners and wallpapers similarly
+    // (i.e. depend on those intrinsic artwork paths rather than
+    // accessing media.{albumBanner,albumWallpaper} from content
+    // or other code directly)
+    return [
+      'media.trackCover',
+      this.directory,
+
+      (artwork.unqualifiedDirectory
+        ? 'cover-' + artwork.unqualifiedDirectory
+        : 'cover'),
+
+      artwork.fileExtension,
+    ];
+  }
 }
 
-export class TrackSectionHelper extends Thing {
+export class TrackSection extends Thing {
   static [Thing.friendlyName] = `Track Section`;
+  static [Thing.referenceType] = `track-section`;
+
+  static [Thing.getPropertyDescriptors] = ({Album, Track}) => ({
+    // Update & expose
 
-  static [Thing.getPropertyDescriptors] = () => ({
     name: name('Unnamed Track Section'),
-    color: color(),
+
+    unqualifiedDirectory: directory(),
+
+    color: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(isColor),
+      }),
+
+      withAlbum(),
+
+      withPropertyFromObject({
+        object: '#album',
+        property: input.value('color'),
+      }),
+
+      exposeDependency({dependency: '#album.color'}),
+    ],
+
+    startCountingFrom: [
+      withStartCountingFrom({
+        from: input.updateValue({validate: isNumber}),
+      }),
+
+      exposeDependency({dependency: '#startCountingFrom'}),
+    ],
+
     dateOriginallyReleased: simpleDate(),
-    isDefaultTrackGroup: flag(false),
-  })
+
+    isDefaultTrackSection: flag(false),
+
+    description: contentString(),
+
+    album: [
+      withAlbum(),
+      exposeDependency({dependency: '#album'}),
+    ],
+
+    tracks: thingList({
+      class: input.value(Track),
+    }),
+
+    // Update only
+
+    reverse: soupyReverse(),
+
+    // Expose only
+
+    directory: [
+      withAlbum(),
+
+      exitWithoutDependency({
+        dependency: '#album',
+      }),
+
+      withPropertyFromObject({
+        object: '#album',
+        property: input.value('directory'),
+      }),
+
+      withDirectory({
+        directory: 'unqualifiedDirectory',
+      }).outputs({
+        '#directory': '#unqualifiedDirectory',
+      }),
+
+      {
+        dependencies: ['#album.directory', '#unqualifiedDirectory'],
+        compute: ({
+          ['#album.directory']: albumDirectory,
+          ['#unqualifiedDirectory']: unqualifiedDirectory,
+        }) =>
+          albumDirectory + '/' + unqualifiedDirectory,
+      },
+    ],
+
+    continueCountingFrom: [
+      withContinueCountingFrom(),
+
+      exposeDependency({dependency: '#continueCountingFrom'}),
+    ],
+  });
+
+  static [Thing.findSpecs] = {
+    trackSection: {
+      referenceTypes: ['track-section'],
+      bindTo: 'trackSectionData',
+    },
+
+    unqualifiedTrackSection: {
+      referenceTypes: ['unqualified-track-section'],
+
+      getMatchableDirectories: trackSection =>
+        [trackSection.unqualifiedDirectory],
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    trackSectionsWhichInclude: {
+      bindTo: 'trackSectionData',
+
+      referencing: trackSection => [trackSection],
+      referenced: trackSection => trackSection.tracks,
+    },
+  };
 
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Section': {property: 'name'},
       'Color': {property: 'color'},
+      'Start Counting From': {property: 'startCountingFrom'},
 
       'Date Originally Released': {
         property: 'dateOriginallyReleased',
         transform: parseDate,
       },
+
+      'Description': {property: 'description'},
     },
   };
+
+  [inspect.custom](depth) {
+    const parts = [];
+
+    parts.push(Thing.prototype[inspect.custom].apply(this));
+
+    if (depth >= 0) {
+      let album = null;
+      try {
+        album = this.album;
+      } catch {}
+
+      let first = null;
+      try {
+        first = this.tracks.at(0).trackNumber;
+      } catch {}
+
+      let last = null;
+      try {
+        last = this.tracks.at(-1).trackNumber;
+      } catch {}
+
+      if (album) {
+        const albumName = album.name;
+        const albumIndex = album.trackSections.indexOf(this);
+
+        const num =
+          (albumIndex === -1
+            ? 'indeterminate position'
+            : `#${albumIndex + 1}`);
+
+        const range =
+          (albumIndex >= 0 && first !== null && last !== null
+            ? `: ${first}-${last}`
+            : '');
+
+        parts.push(` (${colors.yellow(num + range)} in ${colors.green(albumName)})`);
+      }
+    }
+
+    return parts.join('');
+  }
 }
diff --git a/src/data/things/art-tag.js b/src/data/things/art-tag.js
index 3149b310..57e156ee 100644
--- a/src/data/things/art-tag.js
+++ b/src/data/things/art-tag.js
@@ -1,20 +1,35 @@
 export const ART_TAG_DATA_FILE = 'tags.yaml';
 
 import {input} from '#composite';
+import find from '#find';
 import {sortAlphabetically, sortAlbumsTracksChronologically} from '#sort';
 import Thing from '#thing';
+import {unique} from '#sugar';
 import {isName} from '#validators';
+import {parseAdditionalNames, parseAnnotatedReferences} from '#yaml';
 
-import {exposeUpdateValueOrContinue} from '#composite/control-flow';
+import {exitWithoutDependency, exposeDependency, exposeUpdateValueOrContinue}
+  from '#composite/control-flow';
 
 import {
+  additionalNameList,
+  annotatedReferenceList,
   color,
+  contentString,
   directory,
   flag,
+  referenceList,
+  reverseReferenceList,
   name,
+  soupyFind,
+  soupyReverse,
+  urls,
   wikiData,
 } from '#composite/wiki-properties';
 
+import {withAllDescendantArtTags, withAncestorArtTagBaobabTree}
+  from '#composite/things/art-tag';
+
 export class ArtTag extends Thing {
   static [Thing.referenceType] = 'tag';
   static [Thing.friendlyName] = `Art Tag`;
@@ -26,6 +41,7 @@ export class ArtTag extends Thing {
     directory: directory(),
     color: color(),
     isContentWarning: flag(false),
+    extraReadingURLs: urls(),
 
     nameShort: [
       exposeUpdateValueOrContinue({
@@ -39,30 +55,72 @@ export class ArtTag extends Thing {
       },
     ],
 
-    // Update only
+    additionalNames: additionalNameList(),
+
+    description: contentString(),
 
-    albumData: wikiData({
-      class: input.value(Album),
+    directDescendantArtTags: referenceList({
+      class: input.value(ArtTag),
+      find: soupyFind.input('artTag'),
     }),
 
-    trackData: wikiData({
-      class: input.value(Track),
+    relatedArtTags: annotatedReferenceList({
+      class: input.value(ArtTag),
+      find: soupyFind.input('artTag'),
+
+      reference: input.value('artTag'),
+      thing: input.value('artTag'),
     }),
 
+    // Update only
+
+    find: soupyFind(),
+    reverse: soupyReverse(),
+
     // Expose only
 
-    taggedInThings: {
-      flags: {expose: true},
+    descriptionShort: [
+      exitWithoutDependency({
+        dependency: 'description',
+        mode: input.value('falsy'),
+      }),
 
-      expose: {
-        dependencies: ['this', 'albumData', 'trackData'],
-        compute: ({this: artTag, albumData, trackData}) =>
-          sortAlbumsTracksChronologically(
-            [...albumData, ...trackData]
-              .filter(({artTags}) => artTags.includes(artTag)),
-            {getDate: thing => thing.coverArtDate ?? thing.date}),
+      {
+        dependencies: ['description'],
+        compute: ({description}) =>
+          description.split('<hr class="split">')[0],
       },
-    },
+    ],
+
+    directlyFeaturedInArtworks: reverseReferenceList({
+      reverse: soupyReverse.input('artworksWhichFeature'),
+    }),
+
+    indirectlyFeaturedInArtworks: [
+      withAllDescendantArtTags(),
+
+      {
+        dependencies: ['#allDescendantArtTags'],
+        compute: ({'#allDescendantArtTags': allDescendantArtTags}) =>
+          unique(
+            allDescendantArtTags
+              .flatMap(artTag => artTag.directlyFeaturedInArtworks)),
+      },
+    ],
+
+    allDescendantArtTags: [
+      withAllDescendantArtTags(),
+      exposeDependency({dependency: '#allDescendantArtTags'}),
+    ],
+
+    directAncestorArtTags: reverseReferenceList({
+      reverse: soupyReverse.input('artTagsWhichDirectlyAncestor'),
+    }),
+
+    ancestorArtTagBaobabTree: [
+      withAncestorArtTagBaobabTree(),
+      exposeDependency({dependency: '#ancestorArtTagBaobabTree'}),
+    ],
   });
 
   static [Thing.findSpecs] = {
@@ -70,10 +128,19 @@ export class ArtTag extends Thing {
       referenceTypes: ['tag'],
       bindTo: 'artTagData',
 
-      getMatchableNames: tag =>
-        (tag.isContentWarning
-          ? [`cw: ${tag.name}`]
-          : [tag.name]),
+      getMatchableNames: artTag =>
+        (artTag.isContentWarning
+          ? [`cw: ${artTag.name}`]
+          : [artTag.name]),
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    artTagsWhichDirectlyAncestor: {
+      bindTo: 'artTagData',
+
+      referencing: artTag => [artTag],
+      referenced: artTag => artTag.directDescendantArtTags,
     },
   };
 
@@ -82,9 +149,27 @@ export class ArtTag extends Thing {
       'Tag': {property: 'name'},
       'Short Name': {property: 'nameShort'},
       'Directory': {property: 'directory'},
+      'Description': {property: 'description'},
+      'Extra Reading URLs': {property: 'extraReadingURLs'},
+
+      'Additional Names': {
+        property: 'additionalNames',
+        transform: parseAdditionalNames,
+      },
 
       'Color': {property: 'color'},
       'Is CW': {property: 'isContentWarning'},
+
+      'Direct Descendant Tags': {property: 'directDescendantArtTags'},
+
+      'Related Tags': {
+        property: 'relatedArtTags',
+        transform: entries =>
+          parseAnnotatedReferences(entries, {
+            referenceField: 'Tag',
+            referenceProperty: 'artTag',
+          }),
+      },
     },
   };
 
diff --git a/src/data/things/artist.js b/src/data/things/artist.js
index 841d652f..87e1c563 100644
--- a/src/data/things/artist.js
+++ b/src/data/things/artist.js
@@ -5,33 +5,37 @@ import {inspect} from 'node:util';
 import CacheableObject from '#cacheable-object';
 import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import {sortAlphabetically} from '#sort';
-import {stitchArrays, unique} from '#sugar';
+import {stitchArrays} from '#sugar';
 import Thing from '#thing';
 import {isName, validateArrayItems} from '#validators';
 import {getKebabCase} from '#wiki-data';
+import {parseArtwork} from '#yaml';
 
-import {withReverseContributionList} from '#composite/wiki-data';
+import {exitWithoutDependency} from '#composite/control-flow';
 
 import {
+  constitutibleArtwork,
   contentString,
   directory,
   fileExtension,
   flag,
   name,
-  reverseContributionList,
   reverseReferenceList,
   singleReference,
+  soupyFind,
+  soupyReverse,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
 
+import {artistTotalDuration} from '#composite/things/artist';
+
 export class Artist extends Thing {
   static [Thing.referenceType] = 'artist';
   static [Thing.wikiDataArray] = 'artistData';
 
-  static [Thing.getPropertyDescriptors] = ({Album, Flash, Track}) => ({
+  static [Thing.getPropertyDescriptors] = ({Album, Flash, Group, Track}) => ({
     // Update & expose
 
     name: name('Unnamed Artist'),
@@ -43,6 +47,16 @@ export class Artist extends Thing {
     hasAvatar: flag(false),
     avatarFileExtension: fileExtension('jpg'),
 
+    avatarArtwork: [
+      exitWithoutDependency({
+        dependency: 'hasAvatar',
+        value: input.value(null),
+      }),
+
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Avatar Artwork'),
+    ],
+
     aliasNames: {
       flags: {update: true, expose: true},
       update: {validate: validateArrayItems(isName)},
@@ -53,178 +67,65 @@ export class Artist extends Thing {
 
     aliasedArtist: singleReference({
       class: input.value(Artist),
-      find: input.value(find.artist),
-      data: 'artistData',
+      find: soupyFind.input('artist'),
     }),
 
     // Update only
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
-
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
-
-    flashData: wikiData({
-      class: input.value(Flash),
-    }),
-
-    trackData: wikiData({
-      class: input.value(Track),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
     // Expose only
 
-    tracksAsArtist: reverseContributionList({
-      data: 'trackData',
-      list: input.value('artistContribs'),
+    trackArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('trackArtistContributionsBy'),
     }),
 
-    tracksAsContributor: reverseContributionList({
-      data: 'trackData',
-      list: input.value('contributorContribs'),
+    trackContributorContributions: reverseReferenceList({
+      reverse: soupyReverse.input('trackContributorContributionsBy'),
     }),
 
-    tracksAsCoverArtist: reverseContributionList({
-      data: 'trackData',
-      list: input.value('coverArtistContribs'),
+    trackCoverArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('trackCoverArtistContributionsBy'),
     }),
 
-    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'),
+      reverse: soupyReverse.input('tracksWithCommentaryBy'),
     }),
 
-    albumsAsAlbumArtist: reverseContributionList({
-      data: 'albumData',
-      list: input.value('artistContribs'),
+    albumArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumArtistContributionsBy'),
     }),
 
-    albumsAsCoverArtist: reverseContributionList({
-      data: 'albumData',
-      list: input.value('coverArtistContribs'),
+    albumCoverArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumCoverArtistContributionsBy'),
     }),
 
-    albumsAsWallpaperArtist: reverseContributionList({
-      data: 'albumData',
-      list: input.value('wallpaperArtistContribs'),
+    albumWallpaperArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumWallpaperArtistContributionsBy'),
     }),
 
-    albumsAsBannerArtist: reverseContributionList({
-      data: 'albumData',
-      list: input.value('bannerArtistContribs'),
+    albumBannerArtistContributions: reverseReferenceList({
+      reverse: soupyReverse.input('albumBannerArtistContributionsBy'),
     }),
 
-    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'),
+      reverse: soupyReverse.input('albumsWithCommentaryBy'),
     }),
 
-    flashesAsContributor: reverseContributionList({
-      data: 'flashData',
-      list: input.value('contributorContribs'),
+    flashContributorContributions: reverseReferenceList({
+      reverse: soupyReverse.input('flashContributorContributionsBy'),
     }),
 
     flashesAsCommentator: reverseReferenceList({
-      data: 'flashData',
-      list: input.value('commentatorArtists'),
+      reverse: soupyReverse.input('flashesWithCommentaryBy'),
     }),
+
+    closelyLinkedGroups: reverseReferenceList({
+      reverse: soupyReverse.input('groupsCloselyLinkedTo'),
+    }),
+
+    totalDuration: artistTotalDuration(),
   });
 
   static [Thing.getSerializeDescriptors] = ({
@@ -240,18 +141,8 @@ 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] = {
@@ -316,6 +207,16 @@ export class Artist extends Thing {
       'URLs': {property: 'urls'},
       'Context Notes': {property: 'contextNotes'},
 
+      // note: doesn't really work as an independent field yet
+      'Avatar Artwork': {
+        property: 'avatarArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            fileExtensionFromThingProperty: 'avatarFileExtension',
+          }),
+      },
+
       'Has Avatar': {property: 'hasAvatar'},
       'Avatar File Extension': {property: 'avatarFileExtension'},
 
@@ -361,7 +262,12 @@ export class Artist extends Thing {
 
       const artistData = [...artists, ...artistAliases];
 
-      return {artistData};
+      const artworkData =
+        artistData
+          .filter(artist => artist.hasAvatar)
+          .map(artist => artist.avatarArtwork);
+
+      return {artistData, artworkData};
     },
 
     sort({artistData}) {
@@ -389,4 +295,12 @@ export class Artist extends Thing {
 
     return parts.join('');
   }
+
+  getOwnArtworkPath(artwork) {
+    return [
+      'media.artistAvatar',
+      this.directory,
+      artwork.fileExtension,
+    ];
+  }
 }
diff --git a/src/data/things/artwork.js b/src/data/things/artwork.js
new file mode 100644
index 00000000..2a97fd6d
--- /dev/null
+++ b/src/data/things/artwork.js
@@ -0,0 +1,399 @@
+import {inspect} from 'node:util';
+
+import {input} from '#composite';
+import find from '#find';
+import Thing from '#thing';
+
+import {
+  isContentString,
+  isContributionList,
+  isDate,
+  isDimensions,
+  isFileExtension,
+  optional,
+  validateArrayItems,
+  validateProperties,
+  validateReference,
+  validateReferenceList,
+} from '#validators';
+
+import {
+  parseAnnotatedReferences,
+  parseContributors,
+  parseDate,
+  parseDimensions,
+} from '#yaml';
+
+import {withPropertyFromObject} from '#composite/data';
+
+import {
+  exitWithoutDependency,
+  exposeConstant,
+  exposeDependency,
+  exposeDependencyOrContinue,
+  exposeUpdateValueOrContinue,
+} from '#composite/control-flow';
+
+import {
+  withRecontextualizedContributionList,
+  withResolvedAnnotatedReferenceList,
+  withResolvedContribs,
+  withResolvedReferenceList,
+} from '#composite/wiki-data';
+
+import {
+  contentString,
+  directory,
+  reverseReferenceList,
+  simpleString,
+  soupyFind,
+  soupyReverse,
+  thing,
+  wikiData,
+} from '#composite/wiki-properties';
+
+import {withDate} from '#composite/things/artwork';
+
+export class Artwork extends Thing {
+  static [Thing.referenceType] = 'artwork';
+
+  static [Thing.getPropertyDescriptors] = ({
+    ArtTag,
+    Contribution,
+  }) => ({
+    // Update & expose
+
+    unqualifiedDirectory: directory({
+      name: input.value(null),
+    }),
+
+    thing: thing(),
+
+    label: simpleString(),
+    source: contentString(),
+
+    dateFromThingProperty: simpleString(),
+
+    date: [
+      withDate({
+        from: input.updateValue({validate: isDate}),
+      }),
+
+      exposeDependency({dependency: '#date'}),
+    ],
+
+    fileExtensionFromThingProperty: simpleString(),
+
+    fileExtension: [
+      {
+        compute: (continuation) => continuation({
+          ['#default']: 'jpg',
+        }),
+      },
+
+      exposeUpdateValueOrContinue({
+        validate: input.value(isFileExtension),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'thing',
+        value: '#default',
+      }),
+
+      exitWithoutDependency({
+        dependency: 'fileExtensionFromThingProperty',
+        value: '#default',
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'fileExtensionFromThingProperty',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#value',
+      }),
+
+      exposeDependency({
+        dependency: '#default',
+      }),
+    ],
+
+    dimensionsFromThingProperty: simpleString(),
+
+    dimensions: [
+      exposeUpdateValueOrContinue({
+        validate: input.value(isDimensions),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'artistContribsFromThingProperty',
+        value: input.value(null),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'dimensionsFromThingProperty',
+      }).outputs({
+        ['#value']: '#dimensionsFromThing',
+      }),
+
+      exitWithoutDependency({
+        dependency: 'dimensionsFromThingProperty',
+        value: input.value(null),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#dimensionsFromThing',
+      }),
+
+      exposeConstant({
+        value: input.value(null),
+      }),
+    ],
+
+    artistContribsFromThingProperty: simpleString(),
+    artistContribsArtistProperty: simpleString(),
+
+    artistContribs: [
+      withDate(),
+
+      withResolvedContribs({
+        from: input.updateValue({validate: isContributionList}),
+        date: '#date',
+        artistProperty: 'artistContribsArtistProperty',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#resolvedContribs',
+        mode: input.value('empty'),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'artistContribsFromThingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'artistContribsFromThingProperty',
+      }).outputs({
+        ['#value']: '#artistContribs',
+      }),
+
+      withRecontextualizedContributionList({
+        list: '#artistContribs',
+      }),
+
+      exposeDependency({
+        dependency: '#artistContribs',
+      }),
+    ],
+
+    artTagsFromThingProperty: simpleString(),
+
+    artTags: [
+      withResolvedReferenceList({
+        list: input.updateValue({
+          validate:
+            validateReferenceList(ArtTag[Thing.referenceType]),
+        }),
+
+        find: soupyFind.input('artTag'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#resolvedReferenceList',
+        mode: input.value('empty'),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'artTagsFromThingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'artTagsFromThingProperty',
+      }).outputs({
+        ['#value']: '#artTags',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#artTags',
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
+
+    referencedArtworksFromThingProperty: simpleString(),
+
+    referencedArtworks: [
+      {
+        compute: (continuation) => continuation({
+          ['#find']:
+            find.mixed({
+              track: find.trackPrimaryArtwork,
+              album: find.albumPrimaryArtwork,
+            }),
+        }),
+      },
+
+      withResolvedAnnotatedReferenceList({
+        list: input.updateValue({
+          validate:
+            // TODO: It's annoying to hardcode this when it's really the
+            // same behavior as through annotatedReferenceList and through
+            // referenceListUpdateDescription, the latter of which isn't
+            // available outside of #composite/wiki-data internals.
+            validateArrayItems(
+              validateProperties({
+                reference: validateReference(['album', 'track']),
+                annotation: optional(isContentString),
+              })),
+        }),
+
+        data: 'artworkData',
+        find: '#find',
+
+        thing: input.value('artwork'),
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#resolvedAnnotatedReferenceList',
+        mode: input.value('empty'),
+      }),
+
+      exitWithoutDependency({
+        dependency: 'referencedArtworksFromThingProperty',
+        value: input.value([]),
+      }),
+
+      withPropertyFromObject({
+        object: 'thing',
+        property: 'referencedArtworksFromThingProperty',
+      }).outputs({
+        ['#value']: '#referencedArtworks',
+      }),
+
+      exposeDependencyOrContinue({
+        dependency: '#referencedArtworks',
+      }),
+
+      exposeConstant({
+        value: input.value([]),
+      }),
+    ],
+
+    // Update only
+
+    find: soupyFind(),
+    reverse: soupyReverse(),
+
+    // used for referencedArtworks (mixedFind)
+    artworkData: wikiData({
+      class: input.value(Artwork),
+    }),
+
+    // Expose only
+
+    referencedByArtworks: reverseReferenceList({
+      reverse: soupyReverse.input('artworksWhichReference'),
+    }),
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Directory': {property: 'unqualifiedDirectory'},
+      'File Extension': {property: 'fileExtension'},
+
+      'Dimensions': {
+        property: 'dimensions',
+        transform: parseDimensions,
+      },
+
+      'Label': {property: 'label'},
+      'Source': {property: 'source'},
+
+      'Date': {
+        property: 'date',
+        transform: parseDate,
+      },
+
+      'Artists': {
+        property: 'artistContribs',
+        transform: parseContributors,
+      },
+
+      'Tags': {property: 'artTags'},
+
+      'Referenced Artworks': {
+        property: 'referencedArtworks',
+        transform: parseAnnotatedReferences,
+      },
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    artworksWhichReference: {
+      bindTo: 'artworkData',
+
+      referencing: referencingArtwork =>
+        referencingArtwork.referencedArtworks
+          .map(({artwork: referencedArtwork, ...referenceDetails}) => ({
+            referencingArtwork,
+            referencedArtwork,
+            referenceDetails,
+          })),
+
+      referenced: ({referencedArtwork}) => [referencedArtwork],
+
+      tidy: ({referencingArtwork, referenceDetails}) => ({
+        artwork: referencingArtwork,
+        ...referenceDetails,
+      }),
+
+      date: ({artwork}) => artwork.date,
+    },
+
+    artworksWhichFeature: {
+      bindTo: 'artworkData',
+
+      referencing: artwork => [artwork],
+      referenced: artwork => artwork.artTags,
+    },
+  };
+
+  get path() {
+    if (!this.thing) return null;
+    if (!this.thing.getOwnArtworkPath) return null;
+
+    return this.thing.getOwnArtworkPath(this);
+  }
+
+  [inspect.custom](depth, options, inspect) {
+    const parts = [];
+
+    parts.push(Thing.prototype[inspect.custom].apply(this));
+
+    if (this.thing) {
+      if (depth >= 0) {
+        const newOptions = {
+          ...options,
+          depth:
+            (options.depth === null
+              ? null
+              : options.depth - 1),
+        };
+
+        parts.push(` for ${inspect(this.thing, newOptions)}`);
+      } else {
+        parts.push(` for ${colors.blue(Thing.getReference(this.thing))}`);
+      }
+    }
+
+    return parts.join('');
+  }
+}
diff --git a/src/data/things/contribution.js b/src/data/things/contribution.js
new file mode 100644
index 00000000..c92fafb4
--- /dev/null
+++ b/src/data/things/contribution.js
@@ -0,0 +1,302 @@
+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 {flag, simpleDate, soupyFind} from '#composite/wiki-properties';
+
+import {
+  withFilteredList,
+  withNearbyItemFromList,
+  withPropertyFromList,
+  withPropertyFromObject,
+} from '#composite/data';
+
+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),
+    ],
+
+    // Update only
+
+    find: soupyFind(),
+
+    // 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',
+      }).outputs({
+        '#value': '#contributions',
+      }),
+
+      withPropertyFromList({
+        list: '#contributions',
+        property: input.value('annotation'),
+      }),
+
+      {
+        dependencies: ['#contributions.annotation', 'annotation'],
+        compute: (continuation, {
+          ['#contributions.annotation']: contributionAnnotations,
+          ['annotation']: annotation,
+        }) => continuation({
+          ['#likeContributionsFilter']:
+            contributionAnnotations.map(mappingAnnotation =>
+              (annotation?.startsWith(`edits for wiki`)
+                ? mappingAnnotation?.startsWith(`edits for wiki`)
+                : !mappingAnnotation?.startsWith(`edits for wiki`))),
+        }),
+      },
+
+      withFilteredList({
+        list: '#contributions',
+        filter: '#likeContributionsFilter',
+      }).outputs({
+        '#filteredList': '#contributions',
+      }),
+
+      exposeDependency({
+        dependency: '#contributions',
+      }),
+    ],
+
+    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..ace18af9 100644
--- a/src/data/things/flash.js
+++ b/src/data/things/flash.js
@@ -1,13 +1,19 @@
 export const FLASH_DATA_FILE = 'flashes.yaml';
 
 import {input} from '#composite';
-import find from '#find';
 import {empty} from '#sugar';
 import {sortFlashesChronologically} from '#sort';
 import Thing from '#thing';
 import {anyOf, isColor, isContentString, isDirectory, isNumber, isString}
   from '#validators';
-import {parseDate, parseContributors} from '#yaml';
+
+import {
+  parseArtwork,
+  parseAdditionalNames,
+  parseContributors,
+  parseDate,
+  parseDimensions,
+} from '#yaml';
 
 import {withPropertyFromObject} from '#composite/data';
 
@@ -19,16 +25,22 @@ import {
 } from '#composite/control-flow';
 
 import {
+  additionalNameList,
   color,
   commentary,
   commentatorArtists,
+  constitutibleArtwork,
   contentString,
   contributionList,
+  dimensions,
   directory,
   fileExtension,
   name,
   referenceList,
   simpleDate,
+  soupyFind,
+  soupyReverse,
+  thing,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
@@ -39,7 +51,11 @@ 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] = ({
+    Track,
+    FlashAct,
+    WikiInfo,
+  }) => ({
     // Update & expose
 
     name: name('Unnamed Flash'),
@@ -89,30 +105,37 @@ export class Flash extends Thing {
 
     coverArtFileExtension: fileExtension('jpg'),
 
-    contributorContribs: contributionList(),
+    coverArtDimensions: dimensions(),
+
+    coverArtwork:
+      constitutibleArtwork.fromYAMLFieldSpec
+        .call(this, 'Cover Artwork'),
+
+    contributorContribs: contributionList({
+      date: 'date',
+      artistProperty: input.value('flashContributorContributions'),
+    }),
 
     featuredTracks: referenceList({
       class: input.value(Track),
-      find: input.value(find.track),
-      data: 'trackData',
+      find: soupyFind.input('track'),
     }),
 
     urls: urls(),
 
+    additionalNames: additionalNameList(),
+
     commentary: commentary(),
+    creditSources: commentary(),
 
     // Update only
 
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
-
-    trackData: wikiData({
-      class: input.value(Track),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
-    flashActData: wikiData({
-      class: input.value(FlashAct),
+    // used for withMatchingContributionPresets (indirectly by Contribution)
+    wikiInfo: thing({
+      class: input.value(WikiInfo),
     }),
 
     // Expose only
@@ -156,6 +179,25 @@ export class Flash extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    flashesWhichFeature: {
+      bindTo: 'flashData',
+
+      referencing: flash => [flash],
+      referenced: flash => flash.featuredTracks,
+    },
+
+    flashContributorContributionsBy:
+      soupyReverse.contributionsBy('flashData', 'contributorContribs'),
+
+    flashesWithCommentaryBy: {
+      bindTo: 'flashData',
+
+      referencing: flash => [flash],
+      referenced: flash => flash.commentatorArtists,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Flash': {property: 'name'},
@@ -169,8 +211,28 @@ export class Flash extends Thing {
         transform: parseDate,
       },
 
+      'Additional Names': {
+        property: 'additionalNames',
+        transform: parseAdditionalNames,
+      },
+
+      'Cover Artwork': {
+        property: 'coverArtwork',
+        transform:
+          parseArtwork({
+            single: true,
+            fileExtensionFromThingProperty: 'coverArtFileExtension',
+            dimensionsFromThingProperty: 'coverArtDimensions',
+          }),
+      },
+
       'Cover Art File Extension': {property: 'coverArtFileExtension'},
 
+      'Cover Art Dimensions': {
+        property: 'coverArtDimensions',
+        transform: parseDimensions,
+      },
+
       'Featured Tracks': {property: 'featuredTracks'},
 
       'Contributors': {
@@ -179,10 +241,19 @@ export class Flash extends Thing {
       },
 
       'Commentary': {property: 'commentary'},
+      'Credit Sources': {property: 'creditSources'},
 
       'Review Points': {ignore: true},
     },
   };
+
+  getOwnArtworkPath(artwork) {
+    return [
+      'media.flashArt',
+      this.directory,
+      artwork.fileExtension,
+    ];
+  }
 }
 
 export class FlashAct extends Thing {
@@ -219,19 +290,13 @@ export class FlashAct extends Thing {
 
     flashes: referenceList({
       class: input.value(Flash),
-      find: input.value(find.flash),
-      data: 'flashData',
+      find: soupyFind.input('flash'),
     }),
 
     // Update only
 
-    flashData: wikiData({
-      class: input.value(Flash),
-    }),
-
-    flashSideData: wikiData({
-      class: input.value(FlashSide),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
     // Expose only
 
@@ -248,6 +313,15 @@ export class FlashAct extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    flashActsWhoseFlashesInclude: {
+      bindTo: 'flashActData',
+
+      referencing: flashAct => [flashAct],
+      referenced: flashAct => flashAct.flashes,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Act': {property: 'name'},
@@ -275,15 +349,12 @@ export class FlashSide extends Thing {
 
     acts: referenceList({
       class: input.value(FlashAct),
-      find: input.value(find.flashAct),
-      data: 'flashActData',
+      find: soupyFind.input('flashAct'),
     }),
 
     // Update only
 
-    flashActData: wikiData({
-      class: input.value(FlashAct),
-    }),
+    find: soupyFind(),
   });
 
   static [Thing.yamlDocumentSpec] = {
@@ -302,6 +373,15 @@ export class FlashSide extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    flashSidesWhoseActsInclude: {
+      bindTo: 'flashSideData',
+
+      referencing: flashSide => [flashSide],
+      referenced: flashSide => flashSide.acts,
+    },
+  };
+
   static [Thing.getYamlLoadingSpec] = ({
     documentModes: {allInOne},
     thingConstructors: {Flash, FlashAct},
@@ -360,7 +440,9 @@ export class FlashSide extends Thing {
       const flashActData = results.filter(x => x instanceof FlashAct);
       const flashSideData = results.filter(x => x instanceof FlashSide);
 
-      return {flashData, flashActData, flashSideData};
+      const artworkData = flashData.map(flash => flash.coverArtwork);
+
+      return {flashData, flashActData, flashSideData, artworkData};
     },
 
     sort({flashData}) {
diff --git a/src/data/things/group.js b/src/data/things/group.js
index 0dbbbb7f..b40d15b4 100644
--- a/src/data/things/group.js
+++ b/src/data/things/group.js
@@ -1,15 +1,18 @@
 export const GROUP_DATA_FILE = 'groups.yaml';
 
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
+import {parseAnnotatedReferences, parseSerieses} from '#yaml';
 
 import {
+  annotatedReferenceList,
   color,
   contentString,
   directory,
   name,
   referenceList,
+  seriesList,
+  soupyFind,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
@@ -17,7 +20,7 @@ import {
 export class Group extends Thing {
   static [Thing.referenceType] = 'group';
 
-  static [Thing.getPropertyDescriptors] = ({Album}) => ({
+  static [Thing.getPropertyDescriptors] = ({Album, Artist}) => ({
     // Update & expose
 
     name: name('Unnamed Group'),
@@ -27,22 +30,28 @@ export class Group extends Thing {
 
     urls: urls(),
 
-    featuredAlbums: referenceList({
-      class: input.value(Album),
-      find: input.value(find.album),
-      data: 'albumData',
-    }),
+    closelyLinkedArtists: annotatedReferenceList({
+      class: input.value(Artist),
+      find: soupyFind.input('artist'),
 
-    // Update only
+      reference: input.value('artist'),
+      thing: input.value('artist'),
+    }),
 
-    albumData: wikiData({
+    featuredAlbums: referenceList({
       class: input.value(Album),
+      find: soupyFind.input('album'),
     }),
 
-    groupCategoryData: wikiData({
-      class: input.value(GroupCategory),
+    serieses: seriesList({
+      group: input.myself(),
     }),
 
+    // Update only
+
+    find: soupyFind(),
+    reverse: soupyFind(),
+
     // Expose only
 
     descriptionShort: {
@@ -61,9 +70,9 @@ export class Group extends Thing {
       flags: {expose: true},
 
       expose: {
-        dependencies: ['this', 'albumData'],
-        compute: ({this: group, albumData}) =>
-          albumData?.filter((album) => album.groups.includes(group)) ?? [],
+        dependencies: ['this', 'reverse'],
+        compute: ({this: group, reverse}) =>
+          reverse.albumsWhoseGroupsInclude(group),
       },
     },
 
@@ -71,9 +80,9 @@ export class Group extends Thing {
       flags: {expose: true},
 
       expose: {
-        dependencies: ['this', 'groupCategoryData'],
-        compute: ({this: group, groupCategoryData}) =>
-          groupCategoryData.find((category) => category.groups.includes(group))
+        dependencies: ['this', 'reverse'],
+        compute: ({this: group, reverse}) =>
+          reverse.groupCategoriesWhichInclude(group, {unique: true})
             ?.color,
       },
     },
@@ -82,9 +91,9 @@ export class Group extends Thing {
       flags: {expose: true},
 
       expose: {
-        dependencies: ['this', 'groupCategoryData'],
-        compute: ({this: group, groupCategoryData}) =>
-          groupCategoryData.find((category) => category.groups.includes(group)) ??
+        dependencies: ['this', 'reverse'],
+        compute: ({this: group, reverse}) =>
+          reverse.groupCategoriesWhichInclude(group, {unique: true}) ??
           null,
       },
     },
@@ -97,6 +106,25 @@ export class Group extends Thing {
     },
   };
 
+  static [Thing.reverseSpecs] = {
+    groupsCloselyLinkedTo: {
+      bindTo: 'groupData',
+
+      referencing: group =>
+        group.closelyLinkedArtists
+          .map(({artist, ...referenceDetails}) => ({
+            group,
+            artist,
+            referenceDetails,
+          })),
+
+      referenced: ({artist}) => [artist],
+
+      tidy: ({group, referenceDetails}) =>
+        ({group, ...referenceDetails}),
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Group': {property: 'name'},
@@ -104,8 +132,22 @@ export class Group extends Thing {
       'Description': {property: 'description'},
       'URLs': {property: 'urls'},
 
+      'Closely Linked Artists': {
+        property: 'closelyLinkedArtists',
+        transform: value =>
+          parseAnnotatedReferences(value, {
+            referenceField: 'Artist',
+            referenceProperty: 'artist',
+          }),
+      },
+
       'Featured Albums': {property: 'featuredAlbums'},
 
+      'Series': {
+        property: 'serieses',
+        transform: parseSerieses,
+      },
+
       'Review Points': {ignore: true},
     },
   };
@@ -174,17 +216,23 @@ export class GroupCategory extends Thing {
 
     groups: referenceList({
       class: input.value(Group),
-      find: input.value(find.group),
-      data: 'groupData',
+      find: soupyFind.input('group'),
     }),
 
     // Update only
 
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
+    find: soupyFind(),
   });
 
+  static [Thing.reverseSpecs] = {
+    groupCategoriesWhichInclude: {
+      bindTo: 'groupCategoryData',
+
+      referencing: groupCategory => [groupCategory],
+      referenced: groupCategory => groupCategory.groups,
+    },
+  };
+
   static [Thing.yamlDocumentSpec] = {
     fields: {
       'Category': {property: 'name'},
diff --git a/src/data/things/homepage-layout.js b/src/data/things/homepage-layout.js
index 00d6aef5..82bad2d3 100644
--- a/src/data/things/homepage-layout.js
+++ b/src/data/things/homepage-layout.js
@@ -1,8 +1,11 @@
 export const HOMEPAGE_LAYOUT_DATA_FILE = 'homepage.yaml';
 
+import {inspect} from 'node:util';
+
+import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
+import {empty} from '#sugar';
 
 import {
   anyOf,
@@ -11,19 +14,26 @@ import {
   isString,
   isStringNonEmpty,
   validateArrayItems,
-  validateInstanceOf,
   validateReference,
 } from '#validators';
 
 import {exposeDependency} from '#composite/control-flow';
 import {withResolvedReference} from '#composite/wiki-data';
-import {color, contentString, name, referenceList, wikiData}
-  from '#composite/wiki-properties';
+
+import {
+  color,
+  contentString,
+  name,
+  referenceList,
+  soupyFind,
+  thing,
+  thingList,
+} from '#composite/wiki-properties';
 
 export class HomepageLayout extends Thing {
   static [Thing.friendlyName] = `Homepage Layout`;
 
-  static [Thing.getPropertyDescriptors] = ({HomepageLayoutRow}) => ({
+  static [Thing.getPropertyDescriptors] = ({HomepageLayoutSection}) => ({
     // Update & expose
 
     sidebarContent: contentString(),
@@ -31,15 +41,12 @@ export class HomepageLayout extends Thing {
     navbarLinks: {
       flags: {update: true, expose: true},
       update: {validate: validateArrayItems(isStringNonEmpty)},
+      expose: {transform: value => value ?? []},
     },
 
-    rows: {
-      flags: {update: true, expose: true},
-
-      update: {
-        validate: validateArrayItems(validateInstanceOf(HomepageLayoutRow)),
-      },
-    },
+    sections: thingList({
+      class: input.value(HomepageLayoutSection),
+    }),
   });
 
   static [Thing.yamlDocumentSpec] = {
@@ -50,85 +57,231 @@ export class HomepageLayout extends Thing {
       'Navbar Links': {property: 'navbarLinks'},
     },
   };
+
+  static [Thing.getYamlLoadingSpec] = ({
+    documentModes: {allInOne},
+    thingConstructors: {
+      HomepageLayout,
+      HomepageLayoutSection,
+      HomepageLayoutAlbumsRow,
+    },
+  }) => ({
+    title: `Process homepage layout file`,
+    file: HOMEPAGE_LAYOUT_DATA_FILE,
+
+    documentMode: allInOne,
+    documentThing: document => {
+      if (document['Homepage']) {
+        return HomepageLayout;
+      }
+
+      if (document['Section']) {
+        return HomepageLayoutSection;
+      }
+
+      if (document['Row']) {
+        switch (document['Row']) {
+          case 'actions':
+            return HomepageLayoutActionsRow;
+          case 'album carousel':
+            return HomepageLayoutAlbumCarouselRow;
+          case 'album grid':
+            return HomepageLayoutAlbumGridRow;
+          default:
+            throw new TypeError(`Unrecognized row type ${document['Row']}`);
+        }
+      }
+
+      return null;
+    },
+
+    save(results) {
+      if (!empty(results) && !(results[0] instanceof HomepageLayout)) {
+        throw new Error(`Expected 'Homepage' document at top of homepage layout file`);
+      }
+
+      const homepageLayout = results[0];
+      const sections = [];
+
+      let currentSection = null;
+      let currentSectionRows = [];
+
+      const closeCurrentSection = () => {
+        if (currentSection) {
+          for (const row of currentSectionRows) {
+            row.section = currentSection;
+          }
+
+          currentSection.rows = currentSectionRows;
+          sections.push(currentSection);
+
+          currentSection = null;
+          currentSectionRows = [];
+        }
+      };
+
+      for (const entry of results.slice(1)) {
+        if (entry instanceof HomepageLayout) {
+          throw new Error(`Expected only one 'Homepage' document in total`);
+        } else if (entry instanceof HomepageLayoutSection) {
+          closeCurrentSection();
+          currentSection = entry;
+        } else if (entry instanceof HomepageLayoutRow) {
+          if (currentSection) {
+            currentSectionRows.push(entry);
+          } else {
+            throw new Error(`Expected a 'Section' document to add following rows into`);
+          }
+        }
+      }
+
+      closeCurrentSection();
+
+      homepageLayout.sections = sections;
+
+      return {homepageLayout};
+    },
+  });
+}
+
+export class HomepageLayoutSection extends Thing {
+  static [Thing.friendlyName] = `Homepage Section`;
+
+  static [Thing.getPropertyDescriptors] = ({HomepageLayoutRow}) => ({
+    // Update & expose
+
+    name: name(`Unnamed Homepage Section`),
+
+    color: color(),
+
+    rows: thingList({
+      class: input.value(HomepageLayoutRow),
+    }),
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Section': {property: 'name'},
+      'Color': {property: 'color'},
+    },
+  };
 }
 
 export class HomepageLayoutRow extends Thing {
   static [Thing.friendlyName] = `Homepage Row`;
 
-  static [Thing.getPropertyDescriptors] = ({Album, Group}) => ({
+  static [Thing.getPropertyDescriptors] = ({HomepageLayoutSection}) => ({
     // Update & expose
 
-    name: name('Unnamed Homepage Row'),
+    section: thing({
+      class: input.value(HomepageLayoutSection),
+    }),
+
+    // Update only
+
+    find: soupyFind(),
+
+    // Expose only
 
     type: {
-      flags: {update: true, expose: true},
+      flags: {expose: true},
 
-      update: {
-        validate() {
+      expose: {
+        compute() {
           throw new Error(`'type' property validator must be overridden`);
         },
       },
     },
+  });
 
-    color: color(),
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Row': {ignore: true},
+    },
+  };
 
-    // Update only
+  [inspect.custom](depth) {
+    const parts = [];
 
-    // These wiki data arrays aren't necessarily used by every subclass, but
-    // to the convenience of providing these, the superclass accepts all wiki
-    // data arrays depended upon by any subclass.
+    parts.push(Thing.prototype[inspect.custom].apply(this));
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
+    if (depth >= 0 && this.section) {
+      const sectionName = this.section.name;
+      const index = this.section.rows.indexOf(this);
+      const rowNum =
+        (index === -1
+          ? 'indeterminate position'
+          : `#${index + 1}`);
+      parts.push(` (${colors.yellow(rowNum)} in ${colors.green(sectionName)})`);
+    }
 
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
+    return parts.join('');
+  }
+}
+
+export class HomepageLayoutActionsRow extends HomepageLayoutRow {
+  static [Thing.friendlyName] = `Homepage Actions Row`;
+
+  static [Thing.getPropertyDescriptors] = (opts) => ({
+    ...HomepageLayoutRow[Thing.getPropertyDescriptors](opts),
+
+    // Update & expose
+
+    actionLinks: {
+      flags: {update: true, expose: true},
+      update: {validate: validateArrayItems(isString)},
+    },
+
+    // Expose only
+
+    type: {
+      flags: {expose: true},
+      expose: {compute: () => 'actions'},
+    },
   });
 
-  static [Thing.yamlDocumentSpec] = {
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(HomepageLayoutRow, {
     fields: {
-      'Row': {property: 'name'},
-      'Color': {property: 'color'},
-      'Type': {property: 'type'},
+      'Actions': {property: 'actionLinks'},
     },
-  };
+  });
 }
 
-export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
-  static [Thing.friendlyName] = `Homepage Albums Row`;
+export class HomepageLayoutAlbumCarouselRow extends HomepageLayoutRow {
+  static [Thing.friendlyName] = `Homepage Album Carousel Row`;
 
   static [Thing.getPropertyDescriptors] = (opts, {Album, Group} = opts) => ({
     ...HomepageLayoutRow[Thing.getPropertyDescriptors](opts),
 
     // Update & expose
 
+    albums: referenceList({
+      class: input.value(Album),
+      find: soupyFind.input('album'),
+    }),
+
+    // Expose only
+
     type: {
-      flags: {update: true, expose: true},
-      update: {
-        validate(value) {
-          if (value !== 'albums') {
-            throw new TypeError(`Expected 'albums'`);
-          }
+      flags: {expose: true},
+      expose: {compute: () => 'album carousel'},
+    },
+  });
 
-          return true;
-        },
-      },
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(HomepageLayoutRow, {
+    fields: {
+      'Albums': {property: 'albums'},
     },
+  });
+}
 
-    displayStyle: {
-      flags: {update: true, expose: true},
+export class HomepageLayoutAlbumGridRow extends HomepageLayoutRow {
+  static [Thing.friendlyName] = `Homepage Album Grid Row`;
 
-      update: {
-        validate: is('grid', 'carousel'),
-      },
+  static [Thing.getPropertyDescriptors] = (opts, {Album, Group} = opts) => ({
+    ...HomepageLayoutRow[Thing.getPropertyDescriptors](opts),
 
-      expose: {
-        transform: (displayStyle) =>
-          displayStyle ?? 'grid',
-      },
-    },
+    // Update & expose
 
     sourceGroup: [
       {
@@ -151,8 +304,7 @@ export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
 
       withResolvedReference({
         ref: input.updateValue(),
-        data: 'groupData',
-        find: input.value(find.group),
+        find: soupyFind.input('group'),
       }),
 
       exposeDependency({dependency: '#resolvedReference'}),
@@ -160,8 +312,7 @@ export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
 
     sourceAlbums: referenceList({
       class: input.value(Album),
-      find: input.value(find.album),
-      data: 'albumData',
+      find: soupyFind.input('album'),
     }),
 
     countAlbumsFromGroup: {
@@ -169,55 +320,19 @@ export class HomepageLayoutAlbumsRow extends HomepageLayoutRow {
       update: {validate: isCountingNumber},
     },
 
-    actionLinks: {
-      flags: {update: true, expose: true},
-      update: {validate: validateArrayItems(isString)},
+    // Expose only
+
+    type: {
+      flags: {expose: true},
+      expose: {compute: () => 'album grid'},
     },
   });
 
   static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(HomepageLayoutRow, {
     fields: {
-      'Display Style': {property: 'displayStyle'},
       'Group': {property: 'sourceGroup'},
       'Count': {property: 'countAlbumsFromGroup'},
       'Albums': {property: 'sourceAlbums'},
-      'Actions': {property: 'actionLinks'},
-    },
-  });
-
-  static [Thing.getYamlLoadingSpec] = ({
-    documentModes: {headerAndEntries}, // Kludge, see below
-    thingConstructors: {
-      HomepageLayout,
-      HomepageLayoutAlbumsRow,
-    },
-  }) => ({
-    title: `Process homepage layout file`,
-
-    // Kludge: This benefits from the same headerAndEntries style messaging as
-    // albums and tracks (for example), but that document mode is designed to
-    // support multiple files, and only one is actually getting processed here.
-    files: [HOMEPAGE_LAYOUT_DATA_FILE],
-
-    documentMode: headerAndEntries,
-    headerDocumentThing: HomepageLayout,
-    entryDocumentThing: document => {
-      switch (document['Type']) {
-        case 'albums':
-          return HomepageLayoutAlbumsRow;
-        default:
-          throw new TypeError(`No processDocument function for row type ${document['Type']}!`);
-      }
-    },
-
-    save(results) {
-      if (!results[0]) {
-        return;
-      }
-
-      const {header: homepageLayout, entries: rows} = results[0];
-      Object.assign(homepageLayout, {rows});
-      return {homepageLayout};
     },
   });
 }
diff --git a/src/data/things/index.js b/src/data/things/index.js
index 3bf84091..96cec88e 100644
--- a/src/data/things/index.js
+++ b/src/data/things/index.js
@@ -2,20 +2,24 @@ import * as path from 'node:path';
 import {fileURLToPath} from 'node:url';
 
 import {openAggregate, showAggregate} from '#aggregate';
+import CacheableObject from '#cacheable-object';
 import {logError} from '#cli';
 import {compositeFrom} from '#composite';
 import * as serialize from '#serialize';
-
+import {withEntries} from '#sugar';
 import Thing from '#thing';
 
 import * as albumClasses from './album.js';
 import * as artTagClasses from './art-tag.js';
 import * as artistClasses from './artist.js';
+import * as artworkClasses from './artwork.js';
+import * as contributionClasses from './contribution.js';
 import * as flashClasses from './flash.js';
 import * as groupClasses from './group.js';
 import * as homepageLayoutClasses from './homepage-layout.js';
 import * as languageClasses from './language.js';
 import * as newsEntryClasses from './news-entry.js';
+import * as sortingRuleClasses from './sorting-rule.js';
 import * as staticPageClasses from './static-page.js';
 import * as trackClasses from './track.js';
 import * as wikiInfoClasses from './wiki-info.js';
@@ -24,11 +28,14 @@ const allClassLists = {
   'album.js': albumClasses,
   'art-tag.js': artTagClasses,
   'artist.js': artistClasses,
+  'artwork.js': artworkClasses,
+  'contribution.js': contributionClasses,
   'flash.js': flashClasses,
   'group.js': groupClasses,
   'homepage-layout.js': homepageLayoutClasses,
   'language.js': languageClasses,
   'news-entry.js': newsEntryClasses,
+  'sorting-rule.js': sortingRuleClasses,
   'static-page.js': staticPageClasses,
   'track.js': trackClasses,
   'wiki-info.js': wikiInfoClasses,
@@ -77,13 +84,25 @@ function errorDuplicateClassNames() {
 }
 
 function flattenClassLists() {
+  let allClassesUnsorted = Object.create(null);
+
   for (const classes of Object.values(allClassLists)) {
     for (const [name, constructor] of Object.entries(classes)) {
       if (typeof constructor !== 'function') continue;
       if (!(constructor.prototype instanceof Thing)) continue;
-      allClasses[name] = constructor;
+      allClassesUnsorted[name] = constructor;
     }
   }
+
+  // Sort subclasses after their superclasses.
+  Object.assign(allClasses,
+    withEntries(allClassesUnsorted, entries =>
+      entries.sort(({[1]: A}, {[1]: B}) =>
+        (A.prototype instanceof B
+          ? +1
+       : B.prototype instanceof A
+          ? -1
+          :  0))));
 }
 
 function descriptorAggregateHelper({
@@ -142,7 +161,10 @@ function evaluatePropertyDescriptors() {
         }
       }
 
-      constructor.propertyDescriptors = results;
+      constructor[CacheableObject.propertyDescriptors] = {
+        ...constructor[CacheableObject.propertyDescriptors] ?? {},
+        ...results,
+      };
     },
 
     showFailedClasses(failedClasses) {
@@ -172,6 +194,20 @@ function evaluateSerializeDescriptors() {
   });
 }
 
+function finalizeCacheableObjectPrototypes() {
+  return descriptorAggregateHelper({
+    message: `Errors finalizing Thing class prototypes`,
+
+    op(constructor) {
+      constructor.finalizeCacheableObjectPrototype();
+    },
+
+    showFailedClasses(failedClasses) {
+      logError`Failed to finalize cacheable object prototypes for classes: ${failedClasses.join(', ')}`;
+    },
+  });
+}
+
 if (!errorDuplicateClassNames())
   process.exit(1);
 
@@ -183,6 +219,9 @@ if (!evaluatePropertyDescriptors())
 if (!evaluateSerializeDescriptors())
   process.exit(1);
 
+if (!finalizeCacheableObjectPrototypes())
+  process.exit(1);
+
 Object.assign(allClasses, {Thing});
 
 export default allClasses;
diff --git a/src/data/things/language.js b/src/data/things/language.js
index dbe1ff3d..a3f861bd 100644
--- a/src/data/things/language.js
+++ b/src/data/things/language.js
@@ -115,7 +115,7 @@ export class Language extends Thing {
     },
 
     // List of descriptors for providing to external link utilities when using
-    // language.formatExternalLink - refer to util/external-links.js for info.
+    // language.formatExternalLink - refer to #external-links for info.
     externalLinkSpec: {
       flags: {update: true, expose: true},
       update: {validate: isExternalLinkSpec},
@@ -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 +841,50 @@ 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} = {}) {
+  function(value, {
+    unit = false,
+    blankIfZero = false,
+  } = {}) {
+    // Null or undefined value is blank content.
+    if (value === null || value === undefined) {
+      return html.blank();
+    }
+
+    // Zero is blank content, if that option is set.
+    if (value === 0 && blankIfZero) {
+      return html.blank();
+    }
+
     return this.formatString(
       unit
         ? `count.${stringKey}.withUnit.` + this.getUnitForm(value)
@@ -715,6 +896,7 @@ const countHelper = (stringKey, optionName = stringKey) =>
 Object.assign(Language.prototype, {
   countAdditionalFiles: countHelper('additionalFiles', 'files'),
   countAlbums: countHelper('albums'),
+  countArtTags: countHelper('artTags', 'tags'),
   countArtworks: countHelper('artworks'),
   countCommentaryEntries: countHelper('commentaryEntries', 'entries'),
   countContributions: countHelper('contributions'),
@@ -722,6 +904,7 @@ Object.assign(Language.prototype, {
   countDays: countHelper('days'),
   countFlashes: countHelper('flashes'),
   countMonths: countHelper('months'),
+  countTimesFeatured: countHelper('timesFeatured'),
   countTimesReferenced: countHelper('timesReferenced'),
   countTimesUsed: countHelper('timesUsed'),
   countTracks: countHelper('tracks'),
diff --git a/src/data/things/sorting-rule.js b/src/data/things/sorting-rule.js
new file mode 100644
index 00000000..b169a541
--- /dev/null
+++ b/src/data/things/sorting-rule.js
@@ -0,0 +1,386 @@
+export const SORTING_RULE_DATA_FILE = 'sorting-rules.yaml';
+
+import {readFile, writeFile} from 'node:fs/promises';
+import * as path from 'node:path';
+
+import {input} from '#composite';
+import {chunkByProperties, compareArrays, unique} from '#sugar';
+import Thing from '#thing';
+import {isObject, isStringNonEmpty, anyOf, strictArrayOf} from '#validators';
+
+import {
+  compareCaseLessSensitive,
+  sortByDate,
+  sortByDirectory,
+  sortByName,
+} from '#sort';
+
+import {
+  documentModes,
+  flattenThingLayoutToDocumentOrder,
+  getThingLayoutForFilename,
+  reorderDocumentsInYAMLSourceText,
+} from '#yaml';
+
+import {flag} from '#composite/wiki-properties';
+
+function isSelectFollowingEntry(value) {
+  isObject(value);
+
+  const {length} = Object.keys(value);
+  if (length !== 1) {
+    throw new Error(`Expected object with 1 key, got ${length}`);
+  }
+
+  return true;
+}
+
+export class SortingRule extends Thing {
+  static [Thing.friendlyName] = `Sorting Rule`;
+
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    active: flag(true),
+
+    message: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+  });
+
+  static [Thing.yamlDocumentSpec] = {
+    fields: {
+      'Message': {property: 'message'},
+      'Active': {property: 'active'},
+    },
+  };
+
+  static [Thing.getYamlLoadingSpec] = ({
+    documentModes: {allInOne},
+    thingConstructors: {DocumentSortingRule},
+  }) => ({
+    title: `Process sorting rules file`,
+    file: SORTING_RULE_DATA_FILE,
+
+    documentMode: allInOne,
+    documentThing: document =>
+      (document['Sort Documents']
+        ? DocumentSortingRule
+        : null),
+
+    save: (results) => ({sortingRules: results}),
+  });
+
+  check(opts) {
+    return this.constructor.check(this, opts);
+  }
+
+  apply(opts) {
+    return this.constructor.apply(this, opts);
+  }
+
+  static check(rule, opts) {
+    const result = this.apply(rule, {...opts, dry: true});
+    if (!result) return true;
+    if (!result.changed) return true;
+    return false;
+  }
+
+  static async apply(_rule, _opts) {
+    throw new Error(`Not implemented`);
+  }
+
+  static async* applyAll(_rules, _opts) {
+    throw new Error(`Not implemented`);
+  }
+
+  static async* go({dataPath, wikiData, dry}) {
+    const rules = wikiData.sortingRules;
+    const constructors = unique(rules.map(rule => rule.constructor));
+
+    for (const constructor of constructors) {
+      yield* constructor.applyAll(
+        rules
+          .filter(rule => rule.active)
+          .filter(rule => rule.constructor === constructor),
+        {dataPath, wikiData, dry});
+    }
+  }
+}
+
+export class ThingSortingRule extends SortingRule {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    properties: {
+      flags: {update: true, expose: true},
+      update: {
+        validate: strictArrayOf(isStringNonEmpty),
+      },
+    },
+  });
+
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(SortingRule, {
+    fields: {
+      'By Properties': {property: 'properties'},
+    },
+  });
+
+  sort(sortable) {
+    if (this.properties) {
+      for (const property of this.properties.slice().reverse()) {
+        const get = thing => thing[property];
+        const lc = property.toLowerCase();
+
+        if (lc.endsWith('date')) {
+          sortByDate(sortable, {getDate: get});
+          continue;
+        }
+
+        if (lc.endsWith('directory')) {
+          sortByDirectory(sortable, {getDirectory: get});
+          continue;
+        }
+
+        if (lc.endsWith('name')) {
+          sortByName(sortable, {getName: get});
+          continue;
+        }
+
+        const values = sortable.map(get);
+
+        if (values.every(v => typeof v === 'string')) {
+          sortable.sort((a, b) =>
+            compareCaseLessSensitive(get(a), get(b)));
+          continue;
+        }
+
+        if (values.every(v => typeof v === 'number')) {
+          sortable.sort((a, b) => get(a) - get(b));
+          continue;
+        }
+
+        sortable.sort((a, b) =>
+          (get(a).toString() < get(b).toString()
+            ? -1
+         : get(a).toString() > get(b).toString()
+            ? +1
+            :  0));
+      }
+    }
+
+    return sortable;
+  }
+}
+
+export class DocumentSortingRule extends ThingSortingRule {
+  static [Thing.getPropertyDescriptors] = () => ({
+    // Update & expose
+
+    // TODO: glob :plead:
+    filename: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+
+    message: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+
+      expose: {
+        dependencies: ['filename'],
+        transform: (value, {filename}) =>
+          value ??
+          `Sort ${filename}`,
+      },
+    },
+
+    selectDocumentsFollowing: {
+      flags: {update: true, expose: true},
+
+      update: {
+        validate:
+          anyOf(
+            isSelectFollowingEntry,
+            strictArrayOf(isSelectFollowingEntry)),
+      },
+
+      compute: {
+        transform: value =>
+          (Array.isArray(value)
+            ? value
+            : [value]),
+      },
+    },
+
+    selectDocumentsUnder: {
+      flags: {update: true, expose: true},
+      update: {validate: isStringNonEmpty},
+    },
+  });
+
+  static [Thing.yamlDocumentSpec] = Thing.extendDocumentSpec(ThingSortingRule, {
+    fields: {
+      'Sort Documents': {property: 'filename'},
+      'Select Documents Following': {property: 'selectDocumentsFollowing'},
+      'Select Documents Under': {property: 'selectDocumentsUnder'},
+    },
+
+    invalidFieldCombinations: [
+      {message: `Specify only one of these`, fields: [
+        'Select Documents Following',
+        'Select Documents Under',
+      ]},
+    ],
+  });
+
+  static async apply(rule, {wikiData, dataPath, dry}) {
+    const oldLayout = getThingLayoutForFilename(rule.filename, wikiData);
+    if (!oldLayout) return null;
+
+    const newLayout = rule.#processLayout(oldLayout);
+
+    const oldOrder = flattenThingLayoutToDocumentOrder(oldLayout);
+    const newOrder = flattenThingLayoutToDocumentOrder(newLayout);
+    const changed = compareArrays(oldOrder, newOrder);
+
+    if (dry) return {changed};
+
+    const realPath =
+      path.join(
+        dataPath,
+        rule.filename.split(path.posix.sep).join(path.sep));
+
+    const oldSourceText = await readFile(realPath, 'utf8');
+    const newSourceText = reorderDocumentsInYAMLSourceText(oldSourceText, newOrder);
+
+    await writeFile(realPath, newSourceText);
+
+    return {changed};
+  }
+
+  static async* applyAll(rules, {wikiData, dataPath, dry}) {
+    rules =
+      rules
+        .slice()
+        .sort((a, b) => a.filename.localeCompare(b.filename, 'en'));
+
+    for (const {chunk, filename} of chunkByProperties(rules, ['filename'])) {
+      const initialLayout = getThingLayoutForFilename(filename, wikiData);
+      if (!initialLayout) continue;
+
+      let currLayout = initialLayout;
+      let prevLayout = initialLayout;
+      let anyChanged = false;
+
+      for (const rule of chunk) {
+        currLayout = rule.#processLayout(currLayout);
+
+        const prevOrder = flattenThingLayoutToDocumentOrder(prevLayout);
+        const currOrder = flattenThingLayoutToDocumentOrder(currLayout);
+
+        if (compareArrays(currOrder, prevOrder)) {
+          yield {rule, changed: false};
+        } else {
+          anyChanged = true;
+          yield {rule, changed: true};
+        }
+
+        prevLayout = currLayout;
+      }
+
+      if (!anyChanged) continue;
+      if (dry) continue;
+
+      const newLayout = currLayout;
+      const newOrder = flattenThingLayoutToDocumentOrder(newLayout);
+
+      const realPath =
+        path.join(
+          dataPath,
+          filename.split(path.posix.sep).join(path.sep));
+
+      const oldSourceText = await readFile(realPath, 'utf8');
+      const newSourceText = reorderDocumentsInYAMLSourceText(oldSourceText, newOrder);
+
+      await writeFile(realPath, newSourceText);
+    }
+  }
+
+  #processLayout(layout) {
+    const fresh = {...layout};
+
+    let sortable = null;
+    switch (fresh.documentMode) {
+      case documentModes.headerAndEntries:
+        sortable = fresh.entryThings =
+          fresh.entryThings.slice();
+        break;
+
+      case documentModes.allInOne:
+        sortable = fresh.things =
+          fresh.things.slice();
+        break;
+
+      default:
+        throw new Error(`Invalid document type for sorting`);
+    }
+
+    if (this.selectDocumentsFollowing) {
+      for (const entry of this.selectDocumentsFollowing) {
+        const [field, value] = Object.entries(entry)[0];
+
+        const after =
+          sortable.findIndex(thing =>
+            thing[Thing.yamlSourceDocument][field] === value);
+
+        const different =
+          after +
+          sortable
+            .slice(after)
+            .findIndex(thing =>
+              Object.hasOwn(thing[Thing.yamlSourceDocument], field) &&
+              thing[Thing.yamlSourceDocument][field] !== value);
+
+        const before =
+          (different === -1
+            ? sortable.length
+            : different);
+
+        const subsortable =
+          sortable.slice(after + 1, before);
+
+        this.sort(subsortable);
+
+        sortable.splice(after + 1, before - after - 1, ...subsortable);
+      }
+    } else if (this.selectDocumentsUnder) {
+      const field = this.selectDocumentsUnder;
+
+      const indices =
+        Array.from(sortable.entries())
+          .filter(([_index, thing]) =>
+            Object.hasOwn(thing[Thing.yamlSourceDocument], field))
+          .map(([index, _thing]) => index);
+
+      for (const [indicesIndex, after] of indices.entries()) {
+        const before =
+          (indicesIndex === indices.length - 1
+            ? sortable.length
+            : indices[indicesIndex + 1]);
+
+        const subsortable =
+          sortable.slice(after + 1, before);
+
+        this.sort(subsortable);
+
+        sortable.splice(after + 1, before - after - 1, ...subsortable);
+      }
+    } else {
+      this.sort(sortable);
+    }
+
+    return fresh;
+  }
+}
diff --git a/src/data/things/static-page.js b/src/data/things/static-page.js
index 03274979..52a09c31 100644
--- a/src/data/things/static-page.js
+++ b/src/data/things/static-page.js
@@ -7,7 +7,7 @@ import {sortAlphabetically} from '#sort';
 import Thing from '#thing';
 import {isName} from '#validators';
 
-import {contentString, directory, name, simpleString}
+import {contentString, directory, flag, name, simpleString}
   from '#composite/wiki-properties';
 
 export class StaticPage extends Thing {
@@ -30,9 +30,12 @@ export class StaticPage extends Thing {
     },
 
     directory: directory(),
-    content: contentString(),
+
     stylesheet: simpleString(),
     script: simpleString(),
+    content: contentString(),
+
+    absoluteLinks: flag(),
   });
 
   static [Thing.findSpecs] = {
@@ -48,6 +51,8 @@ export class StaticPage extends Thing {
       'Short Name': {property: 'nameShort'},
       'Directory': {property: 'directory'},
 
+      'Absolute Links': {property: 'absoluteLinks'},
+
       'Style': {property: 'stylesheet'},
       'Script': {property: 'script'},
       'Content': {property: 'content'},
diff --git a/src/data/things/track.js b/src/data/things/track.js
index cc49fc24..bcf84aa8 100644
--- a/src/data/things/track.js
+++ b/src/data/things/track.js
@@ -3,14 +3,15 @@ import {inspect} from 'node:util';
 import CacheableObject from '#cacheable-object';
 import {colors} from '#cli';
 import {input} from '#composite';
-import find from '#find';
 import Thing from '#thing';
-import {isColor, isContributionList, isDate, isFileExtension}
+import {isBoolean, isColor, isContributionList, isDate, isFileExtension}
   from '#validators';
 
 import {
   parseAdditionalFiles,
   parseAdditionalNames,
+  parseAnnotatedReferences,
+  parseArtwork,
   parseContributors,
   parseDate,
   parseDimensions,
@@ -18,63 +19,117 @@ import {
 } from '#yaml';
 
 import {withPropertyFromObject} from '#composite/data';
-import {withResolvedContribs} from '#composite/wiki-data';
 
 import {
-  exitWithoutDependency,
   exposeConstant,
   exposeDependency,
   exposeDependencyOrContinue,
   exposeUpdateValueOrContinue,
+  exposeWhetherDependencyAvailable,
 } from '#composite/control-flow';
 
 import {
+  withRecontextualizedContributionList,
+  withRedatedContributionList,
+  withResolvedContribs,
+} from '#composite/wiki-data';
+
+import {
   additionalFiles,
   additionalNameList,
   commentary,
   commentatorArtists,
+  constitutibleArtworkList,
   contentString,
   contributionList,
   dimensions,
   directory,
   duration,
   flag,
+  lyrics,
   name,
   referenceList,
+  referencedArtworkList,
   reverseReferenceList,
   simpleDate,
-  singleReference,
   simpleString,
+  singleReference,
+  soupyFind,
+  soupyReverse,
+  thing,
   urls,
   wikiData,
 } from '#composite/wiki-properties';
 
 import {
   exitWithoutUniqueCoverArt,
-  inferredAdditionalNameList,
-  inheritFromOriginalRelease,
-  sharedAdditionalNameList,
-  trackReverseReferenceList,
-  withAlbum,
+  inheritContributionListFromMainRelease,
+  inheritFromMainRelease,
+  withAllReleases,
   withAlwaysReferenceByDirectory,
   withContainingTrackSection,
+  withCoverArtistContribs,
+  withDate,
+  withDirectorySuffix,
   withHasUniqueCoverArt,
+  withMainRelease,
   withOtherReleases,
   withPropertyFromAlbum,
+  withSuffixDirectoryFromAlbum,
+  withTrackArtDate,
+  withTrackNumber,
 } 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,
+    Artwork,
+    Flash,
+    TrackSection,
+    WikiInfo,
+  }) => ({
     // Update & expose
 
     name: name('Unnamed Track'),
-    directory: directory(),
+
+    directory: [
+      withDirectorySuffix(),
+
+      directory({
+        suffix: '#directorySuffix',
+      }),
+    ],
+
+    suffixDirectoryFromAlbum: [
+      {
+        dependencies: [
+          input.updateValue({validate: isBoolean}),
+        ],
+
+        compute: (continuation, {
+          [input.updateValue()]: value,
+        }) => continuation({
+          ['#flagValue']: value ?? false,
+        }),
+      },
+
+      withSuffixDirectoryFromAlbum({
+        flagValue: '#flagValue',
+      }),
+
+      exposeDependency({
+        dependency: '#suffixDirectoryFromAlbum',
+      })
+    ],
+
+    album: thing({
+      class: input.value(Album),
+    }),
 
     additionalNames: additionalNameList(),
-    sharedAdditionalNames: sharedAdditionalNameList(),
-    inferredAdditionalNames: inferredAdditionalNameList(),
 
     bandcampTrackIdentifier: simpleString(),
     bandcampArtworkIdentifier: simpleString(),
@@ -137,71 +192,57 @@ 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'),
+      withTrackArtDate({
+        from: input.updateValue({
+          validate: isDate,
+        }),
       }),
 
-      exposeUpdateValueOrContinue({
-        validate: input.value(isDate),
-      }),
+      exposeDependency({dependency: '#trackArtDate'}),
+    ],
+
+    coverArtDimensions: [
+      exitWithoutUniqueCoverArt(),
+
+      exposeUpdateValueOrContinue(),
 
       withPropertyFromAlbum({
-        property: input.value('trackArtDate'),
+        property: input.value('trackDimensions'),
       }),
 
-      exposeDependency({dependency: '#album.trackArtDate'}),
-    ],
+      exposeDependencyOrContinue({dependency: '#album.trackDimensions'}),
 
-    coverArtDimensions: [
-      exitWithoutUniqueCoverArt(),
       dimensions(),
     ],
 
     commentary: commentary(),
+    creditSources: commentary(),
 
     lyrics: [
-      inheritFromOriginalRelease({
-        property: input.value('lyrics'),
-      }),
-
-      contentString(),
+      inheritFromMainRelease(),
+      lyrics(),
     ],
 
     additionalFiles: additionalFiles(),
     sheetMusicFiles: additionalFiles(),
     midiProjectFiles: additionalFiles(),
 
-    originalReleaseTrack: singleReference({
+    mainReleaseTrack: singleReference({
       class: input.value(Track),
-      find: input.value(find.track),
-      data: 'trackData',
-    }),
-
-    // Internal use only - for directly identifying an album inside a track's
-    // util.inspect display, if it isn't indirectly available (by way of being
-    // included in an album's track list).
-    dataSourceAlbum: singleReference({
-      class: input.value(Album),
-      find: input.value(find.album),
-      data: 'albumData',
+      find: soupyFind.input('track'),
     }),
 
     artistContribs: [
-      inheritFromOriginalRelease({
-        property: input.value('artistContribs'),
-        notFoundValue: input.value([]),
-      }),
+      inheritContributionListFromMainRelease(),
+
+      withDate(),
 
       withResolvedContribs({
         from: input.updateValue({validate: isContributionList}),
+        thingProperty: input.thisProperty(),
+        artistProperty: input.value('trackArtistContributions'),
+        date: '#date',
       }).outputs({
         '#resolvedContribs': '#artistContribs',
       }),
@@ -215,68 +256,69 @@ export class Track extends Thing {
         property: input.value('artistContribs'),
       }),
 
-      exposeDependency({dependency: '#album.artistContribs'}),
-    ],
+      withRecontextualizedContributionList({
+        list: '#album.artistContribs',
+        artistProperty: input.value('trackArtistContributions'),
+      }),
 
-    contributorContribs: [
-      inheritFromOriginalRelease({
-        property: input.value('contributorContribs'),
-        notFoundValue: input.value([]),
+      withRedatedContributionList({
+        list: '#album.artistContribs',
+        date: '#date',
       }),
 
-      contributionList(),
+      exposeDependency({dependency: '#album.artistContribs'}),
     ],
 
-    // Cover artists aren't inherited from the original release, since it
-    // typically varies by release and isn't defined by the musical qualities
-    // of the track.
-    coverArtistContribs: [
-      exitWithoutUniqueCoverArt({
-        value: input.value([]),
-      }),
+    contributorContribs: [
+      inheritContributionListFromMainRelease(),
 
-      withResolvedContribs({
-        from: input.updateValue({validate: isContributionList}),
-      }).outputs({
-        '#resolvedContribs': '#coverArtistContribs',
-      }),
+      withDate(),
 
-      exposeDependencyOrContinue({
-        dependency: '#coverArtistContribs',
-        mode: input.value('empty'),
+      contributionList({
+        date: '#date',
+        artistProperty: input.value('trackContributorContributions'),
       }),
+    ],
 
-      withPropertyFromAlbum({
-        property: input.value('trackCoverArtistContribs'),
+    coverArtistContribs: [
+      withCoverArtistContribs({
+        from: input.updateValue({
+          validate: isContributionList,
+        }),
       }),
 
-      exposeDependency({dependency: '#album.trackCoverArtistContribs'}),
+      exposeDependency({dependency: '#coverArtistContribs'}),
     ],
 
     referencedTracks: [
-      inheritFromOriginalRelease({
-        property: input.value('referencedTracks'),
+      inheritFromMainRelease({
         notFoundValue: input.value([]),
       }),
 
       referenceList({
         class: input.value(Track),
-        find: input.value(find.track),
-        data: 'trackData',
+        find: soupyFind.input('track'),
       }),
     ],
 
     sampledTracks: [
-      inheritFromOriginalRelease({
-        property: input.value('sampledTracks'),
+      inheritFromMainRelease({
         notFoundValue: input.value([]),
       }),
 
       referenceList({
         class: input.value(Track),
-        find: input.value(find.track),
-        data: 'trackData',
+        find: soupyFind.input('track'),
+      }),
+    ],
+
+    trackArtworks: [
+      exitWithoutUniqueCoverArt({
+        value: input.value([]),
       }),
+
+      constitutibleArtworkList.fromYAMLFieldSpec
+        .call(this, 'Track Artwork'),
     ],
 
     artTags: [
@@ -286,50 +328,50 @@ export class Track extends Thing {
 
       referenceList({
         class: input.value(ArtTag),
-        find: input.value(find.artTag),
-        data: 'artTagData',
+        find: soupyFind.input('artTag'),
       }),
     ],
 
-    // Update only
+    referencedArtworks: [
+      exitWithoutUniqueCoverArt({
+        value: input.value([]),
+      }),
 
-    albumData: wikiData({
-      class: input.value(Album),
-    }),
+      referencedArtworkList(),
+    ],
 
-    artistData: wikiData({
-      class: input.value(Artist),
-    }),
+    // Update only
 
-    artTagData: wikiData({
-      class: input.value(ArtTag),
-    }),
+    find: soupyFind(),
+    reverse: soupyReverse(),
 
-    flashData: wikiData({
-      class: input.value(Flash),
+    // used for referencedArtworkList (mixedFind)
+    artworkData: wikiData({
+      class: input.value(Artwork),
     }),
 
+    // used for withAlwaysReferenceByDirectory (for some reason)
     trackData: wikiData({
       class: input.value(Track),
     }),
 
+    // used for withMatchingContributionPresets (indirectly by Contribution)
+    wikiInfo: thing({
+      class: input.value(WikiInfo),
+    }),
+
     // Expose only
 
     commentatorArtists: commentatorArtists(),
 
-    album: [
-      withAlbum(),
-      exposeDependency({dependency: '#album'}),
-    ],
-
     date: [
-      exposeDependencyOrContinue({dependency: 'dateFirstReleased'}),
-
-      withPropertyFromAlbum({
-        property: input.value('date'),
-      }),
+      withDate(),
+      exposeDependency({dependency: '#date'}),
+    ],
 
-      exposeDependency({dependency: '#album.date'}),
+    trackNumber: [
+      withTrackNumber(),
+      exposeDependency({dependency: '#trackNumber'}),
     ],
 
     hasUniqueCoverArt: [
@@ -337,22 +379,49 @@ export class Track extends Thing {
       exposeDependency({dependency: '#hasUniqueCoverArt'}),
     ],
 
+    isMainRelease: [
+      withMainRelease(),
+
+      exposeWhetherDependencyAvailable({
+        dependency: '#mainRelease',
+        negate: input.value(true),
+      }),
+    ],
+
+    isSecondaryRelease: [
+      withMainRelease(),
+
+      exposeWhetherDependencyAvailable({
+        dependency: '#mainRelease',
+      }),
+    ],
+
+    // Only has any value for main releases, because secondary releases
+    // are never secondary to *another* secondary release.
+    secondaryReleases: reverseReferenceList({
+      reverse: soupyReverse.input('tracksWhichAreSecondaryReleasesOf'),
+    }),
+
+    allReleases: [
+      withAllReleases(),
+      exposeDependency({dependency: '#allReleases'}),
+    ],
+
     otherReleases: [
       withOtherReleases(),
       exposeDependency({dependency: '#otherReleases'}),
     ],
 
-    referencedByTracks: trackReverseReferenceList({
-      list: input.value('referencedTracks'),
+    referencedByTracks: reverseReferenceList({
+      reverse: soupyReverse.input('tracksWhichReference'),
     }),
 
-    sampledByTracks: trackReverseReferenceList({
-      list: input.value('sampledTracks'),
+    sampledByTracks: reverseReferenceList({
+      reverse: soupyReverse.input('tracksWhichSample'),
     }),
 
     featuredInFlashes: reverseReferenceList({
-      data: 'flashData',
-      list: input.value('featuredTracks'),
+      reverse: soupyReverse.input('flashesWhichFeature'),
     }),
   });
 
@@ -360,6 +429,7 @@ export class Track extends Thing {
     fields: {
       'Track': {property: 'name'},
       'Directory': {property: 'directory'},
+      'Suffix Directory': {property: 'suffixDirectoryFromAlbum'},
 
       'Additional Names': {
         property: 'additionalNames',
@@ -413,6 +483,7 @@ export class Track extends Thing {
 
       'Lyrics': {property: 'lyrics'},
       'Commentary': {property: 'commentary'},
+      'Credit Sources': {property: 'creditSources'},
 
       'Additional Files': {
         property: 'additionalFiles',
@@ -429,10 +500,15 @@ export class Track extends Thing {
         transform: parseAdditionalFiles,
       },
 
-      'Originally Released As': {property: 'originalReleaseTrack'},
+      'Main Release': {property: 'mainReleaseTrack'},
       'Referenced Tracks': {property: 'referencedTracks'},
       'Sampled Tracks': {property: 'sampledTracks'},
 
+      'Referenced Artworks': {
+        property: 'referencedArtworks',
+        transform: parseAnnotatedReferences,
+      },
+
       'Franchises': {ignore: true},
       'Inherit Franchises': {ignore: true},
 
@@ -451,34 +527,48 @@ export class Track extends Thing {
         transform: parseContributors,
       },
 
+      'Track Artwork': {
+        property: 'trackArtworks',
+        transform:
+          parseArtwork({
+            dimensionsFromThingProperty: 'coverArtDimensions',
+            fileExtensionFromThingProperty: 'coverArtFileExtension',
+            dateFromThingProperty: 'coverArtDate',
+            artTagsFromThingProperty: 'artTags',
+            referencedArtworksFromThingProperty: 'referencedArtworks',
+            artistContribsFromThingProperty: 'coverArtistContribs',
+            artistContribsArtistProperty: 'trackCoverArtistContributions',
+          }),
+      },
+
       'Art Tags': {property: 'artTags'},
 
       'Review Points': {ignore: true},
     },
 
     invalidFieldCombinations: [
-      {message: `Rereleases inherit references from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit references from the main one`, fields: [
+        'Main Release',
         'Referenced Tracks',
       ]},
 
-      {message: `Rereleases inherit samples from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit samples from the main one`, fields: [
+        'Main Release',
         'Sampled Tracks',
       ]},
 
-      {message: `Rereleases inherit artists from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit artists from the main one`, fields: [
+        'Main Release',
         'Artists',
       ]},
 
-      {message: `Rereleases inherit contributors from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit contributors from the main one`, fields: [
+        'Main Release',
         'Contributors',
       ]},
 
-      {message: `Rereleases inherit lyrics from the original`, fields: [
-        'Originally Released As',
+      {message: `Secondary releases inherit lyrics from the main one`, fields: [
+        'Main Release',
         'Lyrics',
       ]},
 
@@ -499,6 +589,7 @@ export class Track extends Thing {
   static [Thing.findSpecs] = {
     track: {
       referenceTypes: ['track'],
+
       bindTo: 'trackData',
 
       getMatchableNames: track =>
@@ -507,12 +598,12 @@ export class Track extends Thing {
           : [track.name]),
     },
 
-    trackOriginalReleasesOnly: {
+    trackMainReleasesOnly: {
       referenceTypes: ['track'],
       bindTo: 'trackData',
 
       include: track =>
-        !CacheableObject.getUpdateValue(track, 'originalReleaseTrack'),
+        !CacheableObject.getUpdateValue(track, 'mainReleaseTrack'),
 
       // It's still necessary to check alwaysReferenceByDirectory here, since
       // it may be set manually (with `Always Reference By Directory: true`),
@@ -523,32 +614,128 @@ export class Track extends Thing {
           ? []
           : [track.name]),
     },
+
+    trackWithArtwork: {
+      referenceTypes: [
+        'track',
+        'track-referencing-artworks',
+        'track-referenced-artworks',
+      ],
+
+      bindTo: 'trackData',
+
+      include: track =>
+        track.hasUniqueCoverArt,
+
+      getMatchableNames: track =>
+        (track.alwaysReferenceByDirectory
+          ? []
+          : [track.name]),
+    },
+
+    trackPrimaryArtwork: {
+      [Thing.findThisThingOnly]: false,
+
+      referenceTypes: [
+        'track',
+        'track-referencing-artworks',
+        'track-referenced-artworks',
+      ],
+
+      bindTo: 'artworkData',
+
+      include: (artwork, {Artwork, Track}) =>
+        artwork instanceof Artwork &&
+        artwork.thing instanceof Track &&
+        artwork === artwork.thing.trackArtworks[0],
+
+      getMatchableNames: ({thing: track}) =>
+        (track.alwaysReferenceByDirectory
+          ? []
+          : [track.name]),
+
+      getMatchableDirectories: ({thing: track}) =>
+        [track.directory],
+    },
+  };
+
+  static [Thing.reverseSpecs] = {
+    tracksWhichReference: {
+      bindTo: 'trackData',
+
+      referencing: track => track.isMainRelease ? [track] : [],
+      referenced: track => track.referencedTracks,
+    },
+
+    tracksWhichSample: {
+      bindTo: 'trackData',
+
+      referencing: track => track.isMainRelease ? [track] : [],
+      referenced: track => track.sampledTracks,
+    },
+
+    tracksWhoseArtworksFeature: {
+      bindTo: 'trackData',
+
+      referencing: track => [track],
+      referenced: track => track.artTags,
+    },
+
+    trackArtistContributionsBy:
+      soupyReverse.contributionsBy('trackData', 'artistContribs'),
+
+    trackContributorContributionsBy:
+      soupyReverse.contributionsBy('trackData', 'contributorContribs'),
+
+    trackCoverArtistContributionsBy:
+      soupyReverse.artworkContributionsBy('trackData', 'trackArtworks'),
+
+    tracksWithCommentaryBy: {
+      bindTo: 'trackData',
+
+      referencing: track => [track],
+      referenced: track => track.commentatorArtists,
+    },
+
+    tracksWhichAreSecondaryReleasesOf: {
+      bindTo: 'trackData',
+
+      referencing: track => track.isSecondaryRelease ? [track] : [],
+      referenced: track => [track.mainReleaseTrack],
+    },
   };
 
   // Track YAML loading is handled in album.js.
   static [Thing.getYamlLoadingSpec] = null;
 
+  getOwnArtworkPath(artwork) {
+    if (!this.album) return null;
+
+    return [
+      'media.trackCover',
+      this.album.directory,
+
+      (artwork.unqualifiedDirectory
+        ? this.directory + '-' + artwork.unqualifiedDirectory
+        : this.directory),
+
+      artwork.fileExtension,
+    ];
+  }
+
   [inspect.custom](depth) {
     const parts = [];
 
     parts.push(Thing.prototype[inspect.custom].apply(this));
 
-    if (CacheableObject.getUpdateValue(this, 'originalReleaseTrack')) {
-      parts.unshift(`${colors.yellow('[rerelease]')} `);
+    if (CacheableObject.getUpdateValue(this, 'mainReleaseTrack')) {
+      parts.unshift(`${colors.yellow('[secrelease]')} `);
     }
 
     let album;
 
     if (depth >= 0) {
-      try {
-        album = this.album;
-      } catch (_error) {
-        // Computing album might crash for any reason, which we don't want to
-        // distract from another error we might be trying to work out at the
-        // moment (for which debugging might involve inspecting this track!).
-      }
-
-      album ??= this.dataSourceAlbum;
+      album = this.album;
     }
 
     if (album) {
diff --git a/src/data/things/wiki-info.js b/src/data/things/wiki-info.js
index 316bd3bb..590598be 100644
--- a/src/data/things/wiki-info.js
+++ b/src/data/things/wiki-info.js
@@ -1,11 +1,20 @@
 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 {contentString, flag, name, referenceList, wikiData}
+import {parseContributionPresets} from '#yaml';
+
+import {
+  isBoolean,
+  isColor,
+  isContributionPresetList,
+  isLanguageCode,
+  isName,
+  isURL,
+} from '#validators';
+
+import {exitWithoutDependency} from '#composite/control-flow';
+import {contentString, flag, name, referenceList, soupyFind}
   from '#composite/wiki-properties';
 
 export class WikiInfo extends Thing {
@@ -49,14 +58,26 @@ export class WikiInfo extends Thing {
     canonicalBase: {
       flags: {update: true, expose: true},
       update: {validate: isURL},
+      expose: {
+        transform: (value) =>
+          (value === null
+            ? null
+         : value.endsWith('/')
+            ? value
+            : value + '/'),
+      },
     },
 
     divideTrackListsByGroups: referenceList({
       class: input.value(Group),
-      find: input.value(find.group),
-      data: 'groupData',
+      find: soupyFind.input('group'),
     }),
 
+    contributionPresets: {
+      flags: {update: true, expose: true},
+      update: {validate: isContributionPresetList},
+    },
+
     // Feature toggles
     enableFlashesAndGames: flag(false),
     enableListings: flag(false),
@@ -64,11 +85,27 @@ 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
 
-    groupData: wikiData({
-      class: input.value(Group),
-    }),
+    find: soupyFind(),
+
+    searchDataAvailable: {
+      flags: {update: true},
+      update: {
+        validate: isBoolean,
+        default: false,
+      },
+    },
   });
 
   static [Thing.yamlDocumentSpec] = {
@@ -86,6 +123,11 @@ 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,
+      },
     },
   };