Comment by consp
This is correct, though wat probably is meant is that US cars (or dual designed cars) have two spots with only the right one filled in the EU and a separate fog light with only the left one filled. I had a Ford Fiesta with only one reverse light and put in another to get a bit more light when reversing and my assumption is this is more common on US designed vehicles (though the Fiesta was designed in either the UK or Germany but you get the jist).
Of course now it’s basically a non-issue as all new cars have a night-vision camera when in reverse.