How to change datepicker for non-Gregorian calendars?

[dirk]

@ThiefMaster

Keep in mind that this isn’t only a display thing but likely also requires conversions between calendar formats (since Indico will always use and store gregorian dates internally).

I think it is only a display thing. Actually Indico stores the dates in Unix time and does not know about Gregorian or other calendars itself.

The conversion seems to be as simple as the story of Celsius and Fahrenheit: https://www.arabic-for-nerds.com/convert-hijri-date/ (I am not sure about that; can you confirm @Ali_Padida?)
Actually I hoped that it was already implemented in standard libraries when playing with the date translations yesterday. But now I learned at least what the م stands for! Thank you!