The Newark Italian hot dog throws out almost every rule the soft split bun exists to enforce. The dog, usually two, is deep-fried rather than griddled or boiled, and it is loaded not into a slit-top bun but into a quarter or half of round Italian pizza bread hollowed into a pocket, then packed with deep-fried potatoes, peppers, and onions. The defining decision is the bread acting as a vessel instead of a hinge. A standard hot dog bun holds the sausage from below and lets the toppings sit on top; the pizza-bread pocket surrounds the whole load, dogs and fried vegetables together, so the sandwich is eaten from the open end like a packed cone rather than along a split.
The craft is in frying everything and engineering the pocket to hold it. The dogs are fried until the skin blisters and the casing snaps, a deeper, crispier surface than a griddle gives, and they go in still hot. The potatoes are fried in rounds or wedges to a crust that stays crisp against the grease around them, and the peppers and onions are fried soft and sweet so they bind the load rather than slide out. The pizza bread is the structural problem: it has to be a round loaf with a crumb sturdy enough to be hollowed into a deep pocket and still contain a heavy, oily, multi-part filling without splitting at the seam or going to paste from the inside. The pocket is loaded so the dogs anchor the center and the fried potatoes and vegetables pack around them, holding the whole thing in compression so it does not fall out of the open end before it is finished. This is stand-and-eat food built around the deep fryer, wrapped tight so the pocket keeps its shape, and the wrap is doing real structural work.
The Italian hot dog sits in the wider hot dog map next to the other regional builds that change the bun and the cargo, the Chicago order, the coney, the half-smoke, the Sonoran, and the ripper, each engineered so its bread can survive its own specific load. Those are codified builds with their own rules and deserve their own articles rather than being crowded in here.