Comment # 5 on bug 1116498 from Tony Mechelynck

On my system (Leap 15.2 x86-64), /etc/sysconfig/clock contains

TIMEZONE="Europe/Brussels"
DEFAULT_TIMEZONE="GMT"

which is weird, since GMT is neither Brussels's winter time (CET or GMT+0100,
now in vigour) nor its summer time (CEST, GMT+0200, which was legal time until
recently), nor is it the time of my hardware clock (which is set to local time
to allow double-booting Linux / Windows).

In addition, the clock displayed in the Gnome top bar thinks that
Europe/Brussels is summer time and the "date" program knows that it is winter
time, but I'll report a different bug for that.