It took me a minute to figure out what this was even talking about.
Tangles is, apparently, a gitlab-type project where PRs and bug reports and stuff are available on something called "at protocol" which is the bluesky social network "federated protocol".
at protocol competes with ActivityPub, which is mastadon
--
so you could, in theory, have a little federation of gitlabs peer-to-peering with each other, which is desirable for some reason.
except it isn't at all like ActivityPub and is implemented radically differently to avoid many of the problems with ActivityPub.
The "some reason" isn't mysterious... it's redundancy and avoiding a single point of failure and ownership.