ehh said:
I'm not sure if this is intentional or not, but certain redirects don't preserve output format suffixes, e.g.
- https://danbooru.donmai.us/artists/banned.json redirects to https://danbooru.donmai.us/artists?search[is_banned]=true&search[order]=updated_at instead of https://danbooru.donmai.us/artists.json?search[is_banned]=true&search[order]=updated_at;
- https://danbooru.donmai.us/favorites.json?user_id=1 redirects to https://danbooru.donmai.us/posts?tags=ordfav%3Aalbert instead of https://danbooru.donmai.us/posts.json?tags=ordfav%3Aalbert
Those are intentional. Those particular endpoints were removed because they were basically a duplication of function already served by more comprehensive endpoints.