First export from translatewiki.net with https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1090718
- Verify autonym correctness in language-data
- Add to Wikifunctions's language list in function-schemata
- 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
- Check that namespace translations don't conflict with language codes
- Add $linkTrail if needed
- Remove from translatewiki after deploying the core change
- mw-config/LanguageSettings.php
- mw-config/FallbackSettings.php
- Test language search in UniversalLanguageSelector and fix the search index (if needed)