I'd like an en_EU definition to be added, except I went to find an official definition[1], and found the EU uses both.
Elsewhere [2] it says the use of a comma is due to "technical limitations".
I use en_GB or en_IE, but
export TIME_STYLE=long-iso
[1] https://style-guide.europa.eu/en/content/-/isg/topic?identif...
[2] https://commission.europa.eu/system/files/2023-11/styleguide... §6.10.