SomeoneElse
"How things appear on a map" depends on which map you're looking at.  None of the 4 map layers at OpenStreetMap.org do anything special with "ruins", but other maps may do - https://map.atownsend.org.uk/maps/map/map.html#zoom=17&lat=51.844931&lon=-1.29474 is an example of one that does.  It's rendered in a lighter colour to indicate that it's "not quite a building" and the colour of the name indicates "historical".