* John Rouillard <issues@roundup-tracker.org> [20250123 16:27]:
> John Rouillard added the comment:
> > One wish: In roundup we always had the international date format YYYY-MM-DD and
> > it now (at least in my test instance) has mm / dd / yyyy  ... [traditional format
> > ... is dd.mm.yyyy) so can we have the international format back as the default?
> > I guess this *is* configurable?
> 
> Hmm, maybe not or at least not mixable (e.g. English locale with dd.mm.yyyy date
> format).
> 
> The browser is supposed to handle the date format automatically. The date
> (or datetime-local) input takes a YYYY-mm-ddTH:MM[:ss] format value and
> displays it according to the browser's locale (or system date setting (Edge)).

For me it shows as dd / mm / yyyy in Firefox and Chromium, but upon
further investigation I found that it reacts to my
LANG="en_IE.UTF-8" environment variable (which also sets LC_TIME)

If I set it to de_DE.UTF-8, then Firefox incorrectly shows mm / dd / yyyy,
but Chromium shows tt.mm.jjjj

I have chromium-l10n installed, but not firefox-esr-l10n-de, maybe
that causes the different display.

With en_US.UTF-8 both "correctly" show mm / dd / yyyy.

Searching for "custom date input format html5" shows some solutions
to configure the date format to yyyy-mm-dd, e.g.
https://stackoverflow.com/questions/76009630/javascript-to-to-change-input-type-date-format-and-value

But I'm not sure if this is appropriate for Roundup.