I do, but it is still in English , like

 
It should be “Fre. 22. Okt 2021 - 03:20”


%c gives: 
Which is not the locale's date and time format


I did set danish translations for calendar stuff, as you can see



mvh
Niels


 <applewebdata://1DA245BD-24F1-4C64-91AD-483E748BB9CF>
Niels Søndergaard
Mariehøj 236, 2990 Nivå
 <tel:+45 4052 2789>+45 4052 2789niels@algon.dk <mailto:niels@algon.dk>
Ultra posse nemo obligatur.

> Den 21. okt. 2021 kl. 20.18 skrev Eli Zaretskii <eliz@gnu.org>:
> 
>> From: Niels Søndergaard <nisoni@algon.dk>
>> Date: Thu, 21 Oct 2021 20:09:13 +0200
>> Cc: Niels Søndergaard <nisoni@algon.dk>,
>> 51321@debbugs.gnu.org
>> 
>> Actually I can´t figure put, ejere to look for it. I even tried to look in the source, but it just confused me. I´ve looked in most of the documentation without luck…
> 
> You are supposed to customize the option display-time-format.