I made the mistake to look into what is installed into
/usr/lib/systemd/system-shutdown/ on Fedora. fwdupd among other things
assumes /var/ is available from these callouts, though it is not in the
general case.
Hence, let's emphasize this in the documentation a bit more.
Systemd documents "halt" as the primary shutdown mechanism, redirecting
"reboot" and "shutdown" to the halt(8), but halt is a really strange and
obsolete concept. Who would want to really keep their machine running after
shutdown? I expect that halting is almost unused. Let's at least make it less
prominent in the docs.
While at it, use "power off" for a verb and "power-off" for noun (but "poweroff"
of the actual command name).
Lennart Poettering
Zbigniew Jędrzejewski-Szmek