No, it's considerably more involved than that. For example, there's extensive CI: https://www.wireguard.com/build-status/ This thing builds a fresh kernel and boots it for every commit for a bunch of systems. And there's also a lot of long running fuzzing and SAT solving and all sorts of other heavy computation happening during different aspects of development. Development is a bit more than just pushing some code up to Github and hoping for the best.

Thanks for the explanation, I had been under the impression that Wireguard was "done" at this point.