There’s five lines on Wikipedia about “Schloss Heidelberg“. This might be because it is a forgotten place in Switzerland that does not attract THAT much attention.
Not quite our Heidelberger Schloss, probably the most famous ruin in Germany (even Europe?). And yet, the powers that be, far away in the regional capital of Stuttgart, officially use the term Schloss Heidelberg. Minor details that actually make a difference in German. As if it was the building’s name, such as Schönbrunn in Vienna oder Sanssouci in Potsdam. For what it’s worth: There was a place called Heidelberg before the castle came around starting in the 1220s.
It’s just that those in charge don’t seem to know it.