I am not sure that user names that exist in "some" package should be really forbidden. Restricted usernames seem to consist of "well-known" system service usernames.
** Changed in: user-setup (Ubuntu) Status: Unconfirmed => Needs Info -- user-setup allows mythtv to be chosen for a username https://launchpad.net/bugs/86358 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs