Indeed, I completely forgot about the sudo/admin groups. Indeed "admin" has been the one introduced by Ubuntu since the very beginning; later "sudo" was introduced by Debian, and Ubuntu moved to it. So "admin" can safely be dropped once all sudo users got moved into "sudo".
Indeed, I completely forgot about the sudo/admin groups. Indeed "admin" has been the one introduced by Ubuntu since the very beginning; later "sudo" was introduced by Debian, and Ubuntu moved to it. So "admin" can safely be dropped once all sudo users got moved into "sudo".