Funny, cause I thought about it for the fedi project from fedicamp.
But I did not know that there is a name for locale names :)
Due to the lack of wikidata SPARQL to deliver ActivityPub directly (only JSON-LD for full entities), our proxy “learns” well known places from various sources, like OSM, geonames, wiki-voyage -pedia and -data etc.
The thing is that wikidata does list demonyms but does not mark the other -nyms …
E.g. https://www.wikidata.org/wiki/Q980
Also the concept "localized" is unfortunately not covered by ActivityPub multilanguage (which comes from the native JSON-LD multilang.)
What we do is now a two-pass cause wikidata is storing which languages are spoken in the country and so we can separate all the labels in the term endonym and the retronymic antonym.
PS: It is called nucular.