First export from translatewiki.net with https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1161336
[x] Verify autonym correctness in language-data
[x] Add to Wikifunctions's language list in function-schemata https://gitlab.wikimedia.org/repos/abstract-wiki/wikifunctions/function-schemata/-/merge_requests/236
[x] Add to `includes/languages/data/Names.php` ([[ https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1162984 | patch ]])
[x] Add to RELEASE-NOTES ([[ https://gerrit.wikimedia.org/r/c/mediawiki/core/+/1162984 | patch ]])
[] Set fallback if needed (ru)
-- [x] In core (`languages/messages/Messages*.php`)
-- [x] In jquery.i18n (`src/jquery.i18n.fallbacks.js`) ([[ https://github.com/wikimedia/jquery.i18n/pull/305 | patch ]]; depends on [[ https://github.com/wikimedia/jquery.i18n/pull/303 | tests fix ]])
-- [] Remove fallback gender aliases if needed
[x] Add namespace translations ([[ https://translatewiki.net/wiki/User_talk:Sauit#Namespace_translations | requested ]])
-- [x] Check that namespace translations don't conflict with language codes
[x] Add $linkTrail
[] Remove from translatewiki after deploying the core change ([[ https://gerrit.wikimedia.org/r/c/translatewiki/+/1166011 | patch ]])
-- [] `mw-config/LanguageSettings.php`
-- [] `mw-config/FallbackSettings.php`
[x] Test language search in UniversalLanguageSelector and fix the search index (if needed)