As expressed by the English name "rollover camera" adobted for this camera (also known as a "brush" camera"), this device is actually a camera despite its looking like a thick notepad or a book. Its use is quite simple: the book-camera is placed against the document to be copied. One then "brushes" or "sweeps" the device as you would a paintbrush. The little rollers on the edges drive the mechanism and activate the lights ... and document is copied. You dreamed about it, the KGB did it! (source: J.L.Princelle „Authentic Guide to Russian & Soviet Cameras: 2nd Revised Edition", 2004).
The third photo shows the top edge with its LED indicator lights. The green light (the lower one at the right hand end) illuminates while the internal lights are on showing that the scanning speed is correct. The red LED (above this one) indicates the start of the scan and the red LED (at the left hand end) illuminates when the film runs out. The final two photos show the film magazine, which takes 16 mm unperforated film. There is a control knob on the bottom of the unit to adjust the brightness of the internal lamps. The film is advanced by a mechanical linkage to the rollers and does not rely on the batteries (5 x 1.5 Volt Size C LR14). The lens is an Industar with a fixed aperture of f/2.8 and a focal length of 19mm.
Rubin is a commercial camera, no KGB camera.