ActivityPub has a section which deals with how clients and servers should communicate with each other (called Client to Server - C2S - in the spec). So it's the same vocabulary and operations with slightly different side effects, but most servers don't implement it because it's not "specified enough". That's why developers generally just use the Mastodon API.
Yep, I know. That's why I was asking if there was any support other than C2S because that does somewhat limit your server to "basically zero client support" which reduces its usefulness as an example somewhat?
