If GitLab is used for prioprietary projects with a public issue tracker (like we plan to do) there is no way to add labels which are not visible to the public. For example we'd like to add labels for “customer xy” (affected project) or “security”. Customers should not see these labels but see others like “bug”, “feature” etc.
Each label should have permissions like “public” (visible to everyone) or “confidential” (visible only to team).
Links / references
There is already a similar feature request gitlab-ce#9062. While that refers to “private labels” as labels for “only me” (personal labels) this request refers to “confidential labels” as “only for team” which results in completely different implementation details.