None of them appropriately support mailing lists, though. Email-based communication is a big deal for devs which contribute on maybe 5+ projects at once and have to manage comms in one central place.
As for Discourse's mockery of a mailing list mode, let's not even talk about it.
Are you familiar with DFeed [1] used by the D-Lang forum [2]? It is, in my opinion, one of the most usable web frontends for mailing lists (as well as a few other sources).
If you're managing 5+ projects at once, your inbox must be a train-wreck of garbage from these mailing lists.
GitHub has email notifications for issues, but you can opt out of any particular discussion if it gets too pedantic or doesn't relate to you. This helps massively reduce inbox clutter.
The thing that bugs me about mailing lists the most is you get all the email, all the time, forever.
>If you're managing 5+ projects at once, your inbox must be a train-wreck of garbage from these mailing lists.
This is a total non-issue. Mailing lists support daily digests if you want that, and email clients support folders and filters if you want that instead. Nobody managing 5+ mailing list-based projects at once is dumping all of that into an unsorted inbox.