Just had to add a workaround to #Fedify for http://joinmastodon.org/ns, a JSON-LD context URL that has never actually served a JSON-LD document. Mastodon has always inlined the term definitions, but some implementations put it as a bare URL in their @context, so Fedify's JSON-LD processor tries to fetch it and gets a 404 Not Found. Now Fedify ships a bundled copy of a context that never existed in the first place.
https://github.com/fedify-dev/fedify/pull/631
#fedidev #ActivityPub #JSONLD