UserService uses settings indicating User Content Type Id and User Content Type Group Id (userClassID and userGroupClassID), however there's no way to set/customize/override these settings. They either need to be passed as parameter or via some configuration resolver (TBD).

It is needed by EZP-27646.

Please note that there's the bug report EZP-22478 which suggest the opposite action - to make UserService not rely on these settings. I'm not sure which direction is the right one.