Getting extensions into the ActivityStreams 2.0 namespace

ActivityPub seems like the right place for collectively discussing and drafting such documents. Discourse can now publish pages, so the first post of a topic can appear at a stable URL under the /pub namespace. The first post can be fetched via JSON and put into some Git repository, ideally under GitHub - w3c/activitypub or ActivityPub · GitHub

@pukkamustard also proposed: