Documenting roles of developers/reviewers/maintainers
I could not find a documentation that outlines roles of developers/reviewers/maintainers. The closest thing I found is this page in context of code reviews: https://about.gitlab.com/handbook/engineering/#code-reviews
If there isn't one already, would it make sense to create a new page with a pointer from the "Contribution Flow" section in https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md? I think a simple table that is similar to what you see at for the k8s community at https://github.com/kubernetes/community/blob/master/community-membership.md would be a good approach.
Also, my understanding is that "developer" is for people who have gone through on-boarding steps either as GitLab employees or Core Team members. Is there a check list of the on-boarding items? I just scanned through the on-boarding issue that I went though a few weeks ago, but could not identify which ones were relevant for becoming a "developer".