First export from translatewiki with https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1192783
- Verify autonym correctness in language-data
- Add to Wikifunctions's language list in function-schemata
- Add to includes/languages/data/Names.php(patch)
- Add to RELEASE-NOTES
- Set fallback if needed
- In core (languages/messages/Messages*.php)(patch)
- Add namespace translations(asked)(patch)(follow-patch)
- Add gender aliases if needed
- Check that namespace translations don't conflict with language codes
- Add an entry to LocalNames/LocalNamesEn.php in the CLDR extension (if needed)
- Add $linkTrail
- Remove from translatewiki after deploying the core change(patch)
- mw-config/LanguageSettings.php
- Test language search in UniversalLanguageSelector and fix the search index (if needed)