Note that it used to be a bug mainly because Java wasn't giving a lot of locales but according to Thomas Mortagne it changed with Java 11 so it's less of a problem nowadays. Full discussion about this on https://matrix.to/#/!ikPtGZaGWtyblizzlR:matrix.xwiki.com/$17049790791025qISUp:matrix.xwiki.com?via=matrix.org&via=matrix.xwiki.com&via=helsinki-systems.de