@smitten not exactly; bluesky has its own federated protocol which isn't public yet, but which they said, i think, was gonna happen.
some instances which post on the fediverse have the ability to post to multiple different protocols (as opposed to just AcitivityPub) and so some people (me) have been wondering how difficult it'd be to set up an instance that had in its arsenal the bluesky protocol (i think its called ATProtocol)