Box cakes aren't much of a thing in other places, I would be very surprised if any grandma's recipe would include "box cake" here. (I have, in fact, never seen any cake recipe here include box cake)

Box cakes are widely available in most of Europe. They taste more than ok but sure nobody here would claim it’s a family recipe.

Available, sure, but the small sliver they get in the baking aisle probably says all you need to know about the turnover they generate.