First export from translatewiki.net with https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1028246
[ ] Verify autonym correctness in language-data ([[ https://github.com/wikimedia/language-data/pull/341 | patch ]])
[ ] Add to `includes/languages/data/Names.php`
[ ] Add to RELEASE-NOTES
[ ] Set fallback if needed
-- [ ] In core (`languages/messages/Messages*.php`)
-- [ ] In jquery.i18n (`src/jquery.i18n.fallbacks.js`)
-- [ ] Remove fallback gender aliases if needed
[ ] Add namespace translations
-- [ ] Add gender aliases if needed
-- [ ] Check that namespace translations don't conflict with language codes
[ ] Add $linkTrail
[ ] Add date formats (if needed)
[ ] Remove from translatewiki after deploying the core change
-- [ ] `mw-config/LanguageSettings.php`
-- [ ] `mw-config/FallbackSettings.php`
-- [ ] rtl section in [[ https://translatewiki.net/wiki/MediaWiki:Common.css | MediaWiki:Common.css ]] (if needed)
[ ] Test language search in UniversalLanguageSelector and fix the search index if needed