`timedatectl set-timezone` doesn't update `/etc/timezone`

I expected that timedatectl would update /etc/timezone when changing timezones, but no: % sudo timedatectl set-timezone 'Asia/Kuala_Lumpur' % cat /etc/timezone Asia/Bangkok Is there a reason that it doesn't? (Bug?) If I manually update /etc/timezone to match timedatectl set-timezone, are there any side-effects I should be aware of? Is there anywhere else I should consider changing timezone, eg [xfce4 panel clock](https://unix.stackexchange.com/a/227405/143394) ?