Btw the "vapor" barrier is also a water deflector. It tucks into slots at the bottom to return any water back into the quarter cavity to drain out the drain holes.
Behind the blue tape is the slot and the plastic going into it.
This is new plastic copied from the OEM piece and roll calking adhesive applied in the same OEM location.
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This is a front door but it has the same type of slot as the rear
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