FOSS has turned into an exercise in scammer hunting.
Think denying access to production. But allowing changes to staging. Prove yourself in the lower environments (other repos, unlocked code paths) in order to get access to higher envs.
Hell, we already do this in the ops world.
Alternatively they might keep some things open (issues, discussions) while requiring a vouch for PRs. Then, if folks want to get vouched, they can ask for that in discussions. Or maybe you need to ask via email. Or contact maintainers via Discord. It could be anything. Linux isn't developed on GitHub, so how do you submit changes there? Well you do so by following the norms and channels which the project makes visible. Same with Vouch.