v4: API.md says what the URLs are again — it lacked the /playlists pages and GET /api/playlists, a playlist's categories, the ?category= of a user's lists and of the search, and ?chat=<message id>, and its reserved words lacked playlists. It now also states the rules the pages kept without saying: a category is a segment where the page is the category's own and ?category= where it narrows a list on another page; switching tabs takes the place of the history entry, while picking a category or opening another page or an editor adds one; a signed-in page opened signed out comes back after /login. canonical-url.ts named GET /api/dumps/by-url, which is GET /api/dumps?url=.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/lib/canonical-url.ts

@@ -1,9 +1,9 @@
 /**
  * Spots reposts and links to known dumps, by reducing a URL to a key shared by
  * every link to the same page or video. `dump-service` stores it in
- * `dumps.url_canonical` when a dump is posted or edited, `GET
- * /api/dumps/by-url` matches on it to warn the create form of a repost, and
- * backlink-service compares links by it. The key is never fetched or shown, so
+ * `dumps.url_canonical` when a dump is posted or edited, `GET /api/dumps?url=`
+ * matches on it to warn the create form of a repost, and backlink-service
+ * compares links by it. The key is never fetched or shown, so
  * it may be lossy: it forces `https`, drops `www.`, tracking parameters and
  * timestamps.
  *