A collection of mostly vaporware, though the main developer and those around him do seem pretty active on their Goblins (Distributed Programming) front. Mainly mentioning it because of all the namedrops on the front page.
A bit more is better articulated here in this post https://lobste.rs/s/ccseq4/activitypub_secret_weapon_fediverse#c_fa22wk but god damn the terminology soup is still overflowing.
The current federation craze is odd. It's not harmful but I don't know what it's really solving, if anything.