I don't remember ever hearing that called AT proto or AT protocol, just AT commands or AT commandset etc.

Even though I'm that old, even I don't care even if it was anyway.

...as long as the reason is what it looks like. Rather have Bluesky claim it for the purpose of having the officially recognized legal authority to grant usage to everyone else, than have a rando douche company think they can claim it to extort or simply inhibit everyone else.