In Nearby, you can specify a page name, where you want to see related pages in the near in Nearby. This works fine as long as you doesn't have special characters in the URL, which are URL encoded, e.g. this URL will not show anything:
https://de.wikipedia.org/wiki/Spezial:In_der_N%C3%A4he#/page/K%C3%B6lner_Dom
API response from GeoData:
{"servedby":"mw1143","error":{"code":"ggs_invalid-page","info":"Invalid page title ``K%C3%B6lner_Dom'' provided","docref":"See https://de.wikipedia.org/w/api.php for API usage"}}