I think they're talking about Google QUIC, which formed the basis for both IETF QUIC and HTTP/3; Facebook has been deploying Google QUIC for a long while now maybe, AFAIK. The people at fault here are probably the IETF lol.
HTTP/3 implies IETF QUIC. IETF QUIC itself can be used for non-HTTP protocols, though, just like TCP can be used for protocols that aren't HTTP/2.
Maybe I can publish the virtual “WebSocketTransport” thing once I'm satisfied with it.