Why are supposedly ActivityPub-federated Discourse threads inaccessible via external AP clients?

Contribute Bug
10

github.com/mastodon/mastodon/discussions/34600#discussioncomment-13031935 states:

The Discourse AP plugin makes ActivityPub objects available when you click the green ActivityPub logo and click the “Note” button to copy the URL: https://meta.discourse.org/ap/object/5874fad7df806caa1fe34c382c1d2991

Discourse AP needs to make the url link back to the id in some way, preferably via a redirect on requests with the correct Accept content negotiation header.

Consequently, I’ll tentatively set this as a Contribute > Bug. (I can’t. Too old.)