It is starting to be used in more places than just ur/server/registrar. Even now it's used in the RDAP, and we are going to start using it for the registrar-xhr endpoint meaning it will be used in EPP flows as well.
Also logically - this is part of the request authentication.
While moving - we also refactor it to make it easier to use in tests. Instead of mocking, we will be able to create instances with arbitrary roles.
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=221645055