> #ActivityPub supports Groups. I’m wondering if anyone has developed something like a mailing list for AP yet?Yes, they do. I would rather say, they developed exactly a mailing list, which just like the original does not require any special support from the protocol: you just CC it — and a bot behind it reposts the message to all the list subscribers.
> I want to have a technical group ala a mailing list.May I try to dissuade you from doing it? Do not divide the community, let this #fediverse, so far as those who created it, decided to make it an illustration to #XKCD927 , remain a place for posting anime girls, and leave technical talks where they belong to: in full-fledged #mailinglists / #newsgroups.