The actual name of the branch.

The entry point of the project, relative to the project's root

Use this if the branch is of a project that's inside your "entryPoints" setting, simply provide the name of the project (the one inside package.json!)

Use this if you want to generate documentation for a branch of a repository which is completely separate from this documentation, provide a link to the repository. It's recommended that the link excludes the "/tree/branch" part.