I don't know if the situation changed in the more recent releases, but in version 11, what was provided was ActivityStreams but *not* ActivityPub; though that is what was described in the official documentation. Somebody let the marketing department generate press without letting the technical folks proof-read it for accuracy. I looked at it early on to make sure I could federate it with Hubzilla and found that it was simply *not* ActivityPub and could not be coerced to federate with that protocol.