Why does timezonectl not list all timezones available?
$ timedatectl
⋮
Timezone: UTC (UTC, +0000)
⋮
$ timedatectl list-timezones | grep -i utc
-no output-
$ timedatectl list-timezones | wc -l
417
ls /usr/share/zoneinfo
includes UTC, UCT, GMT, Universal, etc. But none of those are included in the list either.
I notice this in CentOS 7, specifically, and have had identical results on two different machines. Interestingly enough, however, Ubuntu shows "UTC" but not "GMT". Which does exist in ./zoneinfo. So the whole thing is quite confusing to me.