FWIW, my first hot dog (described to me by my father as „ein heißer Hund“) was served to me in a long breadroll, made out of European-style white bread (the non-foamy kind). The breadroll was hollowed out and open on one side, so the sausage could be slipped in, along with a helping of (Gewürz?)ketchup. Loved that shit! A bit a googling seems to suggest that these are called “French Hot Dogs”.

Years later I was very confused when I came upon traditional “American” hot dogs.