R1:4811e6e7c122

Require several advanced postgraduate degrees to understand object policies

Summary:
Fixes T11836. See some prior discussion in T8376#120613.

The policy hint in headers in the UI is not exhaustive, and can not reasonably be exhaustive. For example, on a revision, it may say "All Users", but really mean "All users who can see the space this object is in and the repository it belongs to, plus the revision author and reviewers".

These rules are explained if you click (and, often, in the documentation), but…