Limit repos a user has access to

We’re adding a growing number of repositories, including private joint-venture repos. To reduce noise and avoid exposing unrelated/private projects, we would like to limit what each user can see.

We would like to make it so that a user should only be able to see the repositories where they are explicitly assigned as either a reviewer or a contributor

No files, tests, or entry points are named. Begin by locating the repository visibility and reviewer/contributor assignment handling, then verify that users can see only repositories where they hold one of those assignments and that unrelated private repositories remain hidden.

Written by the indexing model from the issue text.