2025-03-03 [04:22:11.0267] sffc: Did you overlook this line: https://github.com/unicode-org/cldr/blob/9931b3281c82cf82f267c12d732f4e207fd4bff3/common/supplemental/supplementalData.xml#L4869 ? Anyway, as I asked on the ICU4X issue: What does `islamic` in CLDR data really mean: Does it mean the behavior in ICU4C or does it mean more generally that a local-to-region observation is used or something else? FWIW, https://web.archive.org/web/20170508214424/http://www.moonsighting.com/calculation-or-sighting.html from 2016 does not match CLDR. [04:26:13.0789] I think it would be a good exercise to try to write an MDN explanation for what `islamic` does and when one would use it instead of `islamic-umalqura`, `islamic-civil`, or `islamic-tbla`. 2025-03-06 [09:56:54.0358] anyone dialed in already? [10:00:57.0424] I'm in the waiting room 2025-03-10 [09:27:24.0824] Looks like the current page that supersedes the archived page is https://www.moonsighting.com/how-countries.html . No idea how the site has come up with the lists.