I would agree. I've wanted to get into Linux kernel development but there's a huge knowledge barrier. (And admittedly, I do have lots to learning that I'm working on learning now before I can really start contributing code). The biggest issue I found is that Ex. stuff from 5 years ago may or may not be relevant, and it's almost impossible to figure out if that's the case besides digging through the code and mailing list. The ./Documentation folder does hold some good stuff, but it's hard to find things and there's no guarantee it actually still applies or if there have been subtle changes.