As of Firefox 153, I intend to turn Intl.LocaleInfo on by default. It has been developed behind the javascript.options.experimental.intl_locale_info preference. Our implementation was contributed by André Bargull, thanks Anba!
Summary:
Intl.LocaleInfo adds locale-specific information APIs to Intl.Locale, including week data, text direction, hour cycle, calendars, collations, numbering systems, and measurement systems. This improves interoperability and enables web developers to build better locale-aware experiences without relying on CLDR data.
Bug to turn on by default:
https://bugzilla.mozilla.org/show_bug.cgi?id=2037069
Specification:
https://github.com/tc39/proposal-intl-locale-info
Standards Body:
TC39
Platform Coverage:
All
Preference:javascript.options.experimental.intl_locale_info
DevTools Bug:
N/A
Extensions Bug:
N/A
Use Counter:
N/A
Standards-Positions Discussion:
N/A
Other Browsers (according to MDN compatibility data):
web-platform-tests:
Covered by Test262, e.g. https://github.com/tc39/test262/tree/main/test/intl402/Locale/prototype.