The person originally responsible for filing a Problem Report.
A person who will either find the right person to solve the problem, or close the PR if it is a duplicate or otherwise not an interesting one.
A mentor is a committer who takes it upon him/her to introduce a new committer to the project, both in terms of ensuring the new committers setup is valid, that the new committer knows the available tools required in his/her work and that the new committer knows what is expected of him/her in terms of behaviour.
The person(s) or organisation whom external code comes from and whom patches are sent to.
People on the mailing list where the request for review is posted.