The membranes separated, and Mr. Hand
These are just plain metal, laminated between plastic. There's a hole in the inner lamination at each pad and the edge connector is exposed.
The little stubs you see near the base of Mr. Hand's little finger are to bridge between the upward-facing contacts on the lower
sheet and the edge connector on the PCB. (well, "downward" and "upper" when it's in use.)
If the keyboard is lying on the keys when
you open it then those little rubbery pink cuppy-thingies fall on the floor, and you can find all but one if you want to put the
keyboard back into use as a keyboard. You have been warned. :-)