It’s complicated. 😁

ActivityPub (and ActivityStreams) have never had a standard quote post mechanism, and still don’t. The fediverse has had semi-standard quote posts for years, via a FEP, which Bridgy Fed has supported for years. Mastodon added their own different mechanism, via their own new FEP, which is more powerful but also drastically more complicated, so we haven’t been able to prioritize the work it would take to support it yet. Background in https://github.com/snarfed/bridgy-fed/issues/1956