I did an audit of OSS repos once and have found that most CONTRIBUTING files don't have the technical depth or actually mean to onboard devs to their codebase. Most READMEs have more how-to-run details.

Most teams I talk to manage whole wikis and handbooks to bring new devs into the team.

Would love to jump on a Copilot hacking session with you to see what issues you hit and file detailed issues for us to tackle. The issue from your last GH Copilot session also didn't come up in my issue triage so far.