Yeah, I agree about the docs. I started on the system design page and my head started to swim after about 5 minutes. So exhausting to read!
On the flip side, I expect the project itself will be workable - well, assuming they're actually using it themselves! UE is a big pile of Stuff on its own, and Fortnite must have god knows how much additional crap in there, so if this is (or will be) their replacement for Perforce internally, then it'll be getting a good deal of testing. (If they're just chucking it over the wall, though... well, sheesh, you first...)
(Perforce is the standard thing for games, and pretty well it works too, and hopefully this will deliver it a well-needed kick. It was sold to private equity about 10 years ago, and it feels like they've been coasting ever since. (Perhaps users in other sectors are happier though?))