Panko is bread baked with electricity. Traditional panko makers run current through the dough between two metal plates, so the loaf cooks from the inside out and never forms a crust. The loaf is dried, then shredded into slivers instead of ground into crumbs.
That's why panko fries differently from regular bread crumbs. A crust is a dense browned layer, and ground crumbs are small and tight, so they pack onto the food and soak up oil. Panko slivers are airy and oblong, they sit loosely in the coating, and steam vents out between them, so the coating takes on less oil and stays crisp after it cools. Kikkoman's box says the crumbs come from crustless bread, that they're larger and lighter than regular crumbs, and that they retain less oil. The ingredients are wheat flour, cane sugar, yeast and salt.
The electrode method goes back to a Japanese army field oven from the 1930s. Not every bag labeled panko is made that way, and Japanese style on a US label isn't regulated.