It's pretty obvious (to me) from the shape of the valve covers that there are no belts. The bumps on the one side of the visible valve cover suggest gears between the two camshafts, although I would imagine that there is a primary gear underneath that is chain driven. (wouldn't be the first engine to do it that way)
Elsewhere it has been suggested that it is a 90 degree V-twin with 70-degree offset crank pins. That's going to mean an exceptionally odd irregular firing pattern. Current Ducati twins fire 270 - 450 degrees apart. They talk about a "twin pulse" firing pattern ... I suspect this means that each crank pin has the same (as previous) firing pattern but one of them trails the other by 70 degrees. Firings would be at 0 - 70 - 270 - 340, thus the firing intervals are 70 - 200 - 70 - 380, thus sounding kinda like a V-twin but not really ... There are quite a few other possible firing patterns with what has been described but they wouldn't fit the "twin pulse" description.