In reality though he who controls the source control repository controls the code. They won't just let anyone check in changes willly nilly into the official repository. You could always make a copy of the current code into a repository that you control and start releasing your own builds, but nobody would likely use them over the official builds.
There is nothing "official" about the most commonly used builds.
The fact that a large percentage of users currently prefer that particular build doesn't make it "official", it just makes it popular.
