There should be a foam gasket around the opener to stop drafts. There are only a few Volkswagens where this gasket is still present, and if it is, it's usually leftover foam that can no longer perform any function.
You assemble the opener by sliding the control rod through the foam seal. When the door is completely assembled, you stretch the protective foil over the door, the foam seal is then between the metal of the door and the foil.
This is not a universal custom-made piece of foam rubber, but an identical reproduction in which the recess for the control rod is present and the control rod is completely surrounded by the foam rubber.
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