> PRs and code review are not. CI/CD is not.

They can be. A PR can be made and code review conducted by submitting a patch to a mailing list. That's how the kernel and, I think, git itself is developed.

CI/CD is really a methodology. It just means integrating/deploying stuff as soon as its ready. So you just need maintainers to be able to run the test suite and deploy, which seems like a really basic thing.