Maintainers are responsible for issue/PR triage, feature additions, maintenance, bugfixes, security fixes, releases, promoting existing contributors to maintainers, managing repo and CI configuration, etc.
Promoting contributors to maintainers is done by a maintainer after a significant number of high-quality PRs.
Anyone who contributes code or content or time, via issues or pull requests or otherwise. Contributors have access to triaging issues/PRs and commit access to the repository.
Anyone who contributes code or content or time, via issues or pull requests or otherwise. Outside Contributors do not have any additional permissions on the project.