@ArtBear@mastodonapp.uk off the top of my head is not so much that there are groups in ActivityPub as much as the standard explicitly says that an ID doesn't have to necessarily be an individual user, so it can be a group.
Off the top of my head I don't remember any group functionality beyond that, saying you can be a group.
So I circled back to this question of whether #ActivityPub supported groups, to check/refresh my memory, and it looks like I was half right.
(and I hope my quick skimming now isn't missing something else)
ActivityPub brings in the ActivityStreams standard and its actor concept, and while "This specification intentionally defines Actors in only the most generalized way" leaving the door open to different types of Actors, including groups, it goes on to list specific examples:
"VCard [ vcard-rdf] should be used to provide additional metadata for Person, Group, and Organization instances."
So I *think* that does mean AP explicitly recognizes groups, whether this vcard functionality is implemented anywhere or not.
https://www.w3.org/TR/activitystreams-core/#actors
@ArtBear@mastodonapp.uk
@kurtsh @JonChevreau
