Fancy way of saying live axle, yes.
From the exploded view diagram, it appears the brake drum and the drive sprocket are a "unibody" design assembly. One-piece from the factory. It's only supposed to be keyed to the axle. No welds or other funny business.
Most of the prior karts Manco made, the axle was exposed and supported by bearing hangers right from the frame. This one and a few others have it riding inside a sleeve, a casing, sort of automotive style.