Those 3 groups are the groups we add to our product since phpBB does not have any usergroups by default. The user user_level as an indicator that a user is admin. They use the fact the user is logged in to grant permission and then no login to grant unregistered permissions. Hense no usergroup functionality by default.
If you have not added any usergroups in phpbb for moderators there would be nothing for us to pull. You would need to add this and refresh groups.
phpBB is pretty weak in the usergroups permissions game hense probally the number one reason people switch from that message board to others.