Some language codes appear with autonyms in wmgExtraLanguageNames [[ https://noc.wikimedia.org/conf/highlight.php?file=InitialiseSettings.php | Wikimedia's InitialiseSettings.php ]].
They should be in harmony with the definitions in [[ https://github.com/wikimedia/language-data | language-data ]] on GitHub and [[ https://github.com/wikimedia/mediawiki/blob/master/languages/data/Names.php | Names.php ]].
Here's what I see at the moment (they all appear twice, for wikidata and for commons):
[ ] `'dag' => 'Dagbanli', // T260037, T272242` - Appears in Names.php and can probably be removed (but please verify)
[ ] `'fkv' => 'kvääni', // T167259` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'kea' => 'Kabuverdianu', // T127435` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'nod' => 'ᨣᩴᩤᨾᩮᩥᩬᨦ', // T93880` - Complicated. The autonym in wmgExtraLanguageNames is in the Tai Tham script, and the autonym in language-data is in the Thai script. Both are probably useful, but for clarification it would be great to discuss this with a speaker.
[ ] `'ota' => 'لسان توركى', // T59342` - This says "Turkish language" and language-data says "لسان عثمانى", which is "Ottoman language". They should be the same.
[ ] `'rmf' => 'kaalengo tšimb', // T226701` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'rwr' => 'मारवाड़ी', // T61905` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'sjd' => 'Кӣллт са̄мь кӣлл', // T226701` - Capitalized in wmgExtraLanguageNames, but not in language-data. One of them should be changed. My guess is that it should not be capitalized, but I'll be fine with whatever @Yupik, @Susannaanas, or @jhsoby say.
[ ] `'sje' => 'bidumsámegiella', // T146707` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'sju' => 'ubmejesámiengiälla', // T226701` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'smj' => 'julevsámegiella', // T146707` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'sms' => 'nuõrttsääʹmǩiõll', // T220118, T223544` - Equal to language-data and doesn't appear in Names.php, probably no action needed
[ ] `'srq' => 'mbia cheë', // T113408` - Doesn't appear in language-data, should be added