The mystery attachment on the left, might be a darning hopper?
Courtesy of Odile Berget
German instructions and attachment with chain adjustment.
Courtesy of Sue
The Pfaff 30 and 31 came with a hook to suspend the presser bar, because the presser bar lifting lever has to be lowered in order to retain the needle thread tension which is also required for embroidering. The hook catches in the presser bar clamp screw first then the presser bar is pulled up with the hook and the bent end is inserted in the hole in the face plate.
Courtesy of Claire Sherwell