13:16
<hsivonen>
I looked for the islamic and islamic-rgsa calendars in HTTP Archive. Most matches were bundlers including a chunk of CLDR data. Then false positives (not calendar) for "islamic" in quotes. Finally, I narrowed the list to 6 URLs that might actually be about relevant usage. None show islamic-rgsa. All 6 are either under .sa or .ae. Of these, 5 seem to format a date using islamic. I can't tell if these pages get the results they want, because today islamic agrees with islamic-umalqura. Need to re-test on a day when they don't. Anyway, I'm pretty sure at least the .sa pages would be better off using islamic-umalqura.
13:17
<hsivonen>
CC eemeli dminor sffc
13:19
<hsivonen>
CLDR says .ae prefers Umm al-Qura, too.
13:21
<hsivonen>
Interestingly, mapping the calender by region might make more of a mess, since I see pages under .sa use ar-FR-u-ca-islamic and ar-TN-u-ca-islamic. No idea why.
13:29
<hsivonen>
Also, earlier today, I opened https://github.com/mdn/content/pull/39012