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MacBook Pro 15" Retina Display Late 2013 Display Assembly
The warning about not damaging the keyboard ribbon cable references the cable that is below the rectangular (covered) circuit board that the battery connector comes out of. Below this covered chip (at the top-center of the two central battery packs), the keyboard ribbon cable runs over a small edge and down to where the track pad is. The black cover that the battery packs sit on protects the track pad and this ribbon, but it’s still VERY possible to damage or otherwise destroy the ribbon cable. I would recommend staying away from a 2cm^2 area at the very top-center of the two central battery packs (closest to the battery/main board connector). This will help prevent the plastic cards from suddenly breaking through the glue and striking the ribbon cable if you apply too much force.
Confirmed; if the foam pieces are not perfectly rectangular, you should be able to pry back the side of the foam with the cut-away. It folds in half. You can see the lever under the foam. Lift the handle with the spudger, then when it’s pointing straight up (it flips up), you can lift up on the lever (straight up). This should be done for both ends.