You have a point there, although temporary/ephemeral only holds for utmp. wtmp (and btmp) are more like logs; so they are temporal, but that's really not the ex

You have a point there, although temporary/ephemeral only holds for utmp. wtmp (and btmp) are more like logs; so they are temporal, but that's really not the expected meaning of `tmp` in Unix. utime appeared in V7, while utmp appeared in V6, so that is no excuse either (unless the name was already used internally).