From what I’ve seen, people start off by working with the code until they become trusted enough to be offered the job. More specifically they have contributed code and have been involved in the community to the point where they have knowledge+expertise of a subsystem such that they are as capable or more than the current/prior maintainers.

I presume that that is exactly why it’s hard to find maintainers. There’s plenty of web devs out in the world, but fairly few low level people.

Project Eudyptula was an interesting attempt - basically a set of programming challenges that build up to actually submitting a kernel patch.

It’s on hiatus now though, but they still let existing users finish. I should try and find my old challenge emails and finish them!

http://eudyptula-challenge.org/