https://github.com/wikimedia/wikidata-query-gui/blob/master/embed.html#L256 and many other places hardcode https://query.wikidata.org URL.
It makes it impossible to host it somewhere else with a local DB, and to perform proper tests unbound to production.
P.S. reported at https://www.mediawiki.org/wiki/Topic:Twnti584yjng6fcc