Seems like (at least in Xubuntu 19.04) that the clock uses "%d %b, %H:%M". Both the panel clock and the lightdm-greeter clock. I would like date and time to follow the locale. So if i use danish_denmark (da_DK) it should use the standard way for that country/language. Does Xfce not follow such a locale system so time/date will appear correct according to the locale in use? Sure you can add "%d %b, %H:%M" to be translated in the po files for each piece of software but that would not be smart. Cant see what version i have. How do i check it?
It seems to me that the clock pluging is buggy. Try with the date-time pluging.
datetime-plugin also does not follow the format/locale i would like. The day and month is translated but none of the choices is formatted according the locale. I think the default is: 1999-12-31 So for danish i might want: Søndag, 12. december 2019 31-12-2019 Sure i could make the changes manually but would be smart if Xfce software could follow the local so users dont have to make small adjustments in each software.
So in general the clock plugin cannot really follow the locale, but translators are doing that for the upstream default %R. As users can specify their own custom formats those will not be localized. What I will do though is change the upstream default (that was planned anyway) to the same layout as is currently found in Xubuntu so at least this setup will be locale-dependent.
Simon Steinbeiss referenced this bugreport in commit 2c69eeb88871829d165b480d8ad9b6a704e09568 clock: Add date to default clock layout (Bug #15456) https://git.xfce.org/xfce/xfce4-panel/commit?id=2c69eeb88871829d165b480d8ad9b6a704e09568
I'm not sure this patch fixes the issue in the way you would want but it's pretty much as far as we can go currently.