<<And he has a product name! Googling for 'leak stopper roof tape'
brings up some leads, and from there leads one to Google for ' "Peel &
Seal" roof tape'. This looks like the stuff! Yes!>>

This stuff is just flashing tape.
 Right?

It's not a sound deading material as Q-Pads or any other " In the door,
or  interior panel" material is.
Right?

It's just basicly a vapor barrier.
Correct?