The fact that jars of marmalade are usually labeled "orange marmalade" is a hint that it used to be made from something else, just like tomato ketchup was not a

The fact that jars of marmalade are usually labeled "orange marmalade" is a hint that it used to be made from something else, just like tomato ketchup was not always made with tomatoes. (Ketchup used to be a kind of fish sauce from Southeast Asia.)