From the GitHub Open Source Guide and GitHub Help.
- Author: The person/s or organization that created the project
- Owner: The person/s who has administrative ownership over the organization or repository (not always the same as the original author)
- Maintainers: Contributors who are responsible for driving the vision and managing the organizational aspects of the project. (They may also be authors or owners of the project.)
- Contributors: Everyone who has contributed something back to the project.
- Community Members: People who use the project. They might be active in conversations or express their opinion on the project’s direction.
- An outside collaborator is a person who isn’t explicitly a member of your organization, but who has Read, Write, or Admin permissions to one or more repositories in your organization.