Besides containing the underused hash brown, the Big Bacon Whopper also contains a large slab of flame-grilled thick bacon whose length is about twice that of the bun. They're calling it "King's bacon" (back bacon by the looks of it). The rest of the burger is a standard Whopper (beef patty, lettuce, tomato, onions, mayo, and ketchup).
The BK Bolognese features a pork patty, cheese, hash brown, onions, and a Bolognese sauce.
