Here is an interesting case:
<https://meta.wikimedia.org/wiki/Talk:Language_committee#Requests_for_new_languages.2FWikipedia_Tunica>; the mentioned TWN discussion is at <https://translatewiki.net/wiki/Thread:Support/Please_enable_Tunica_for_translation/reply>

The language <https://en.wikipedia.org/wiki/Tunica_language> (ISO 639-3: tun) is extinct, but apparently there are revitalisation efforts. Does anyone know more about these efforts and their "quality"? The policy, of course, would require "a sufficient number of living native speakers to form a viable community and audience".