Recently the French site setechnic.com published a detailed review (Google Translate is our friend). But even without any French knowledge one can figure out what Lés photos" and "La video" means.
There are four motors, all of them in the superstructure.
The motors drive the functions through a gearbox-like transmission in six different ways: the whole excavator can move forward and backward, steer left or right, the superstructure can be rotated and the arm can be moved in three different ways.
It is interesting how the motors located in the superstructure can drive the threads. Like this:
The gear at the bottom is familiar from 8880 - it rotates around the axle.
You should certainly look at the photos ("Les photos"), they even have a couple of shots showing the list of all parts.
Finally, a video: