The name relates to the many tourist coming to Heidelberg and wanting to see Heidelberg Castle (Heidelberger Schlo&szlig;). If they cannot find their way there, you often get asked "Could you tell me where the SchloB is?" - not being aware that the '&szlig;' ist not a 'B' but should in fact be pronounced like 'ss'.

...often an obvious answer would be: "If you look up from your map you could actually see it..."