What is expected from a candidate when applying to the committers list

Context: https://github.com/NixOS/nixpkgs-committers/issues/50#issue-2367548371

(This is not a request to add me to the committers list.)

I'd like to understand what is expected from a candidate before applying. There are examples above the thread of different stature, and so it's hard to say what the actual bar is just by looking at these. I git grep'ed over the repo for committer but nothing specific popped up. I understand that, ultimately, it's up for the existing team to agree, but I assume their deliberation over a candidate is based on some standards / guidelines. I'd love to see those.

Originally posted by @booxter in #321665

Update Since this is a rather opened ended question, I would consider this issue closed when we have publicly documented what we expect from nominees.

Review the discussion linked from issue #63, especially issue #50 and its referenced comment, to understand the existing expectations. Document the agreed nominee criteria in a public project location; done when expectations for committers-list candidates are publicly documented.