https://www.wikidata.org/wiki/Q3141
It’s linked on that Wikipedia article. It’s very useful to connect data independent of language. OSM can use it to connect places to more data. I think searxng uses it to generate infoboxes
It’s enough to automatically extract coordinates and compare that to your location. For an area comparation it is connected to the OSM relation https://www.openstreetmap.org/relation/4246124 among other things. Getting actual areas is pretty hard due to heterogene data
Q3141 is actually enough to know what it is
Each item is allocated a unique persistent identifier called its QID, a positive integer prefixed with the upper-case letter "Q"