Tape on Door - Simple Question

This question is for a 1995 GMC Sonoma. I've been piddling around with it cleaning it up and removing interior panels and the carpet and things like that to get more space on the inside of the cab and improve cleanliness. Question is, does the little strip of tape on both doors near the top of the window prevent rain from coming in or is it unnecessary? Will post a picture if needed but it's clear tape and I'd like to remove it. It's about a centimeter wide and runs half the length of the top of the window at the top where it starts to turn down, in between the door and the black plastic weather stripping that is the primary insulator of the car from the the air outside and the rain. And if it doesn't have anything to do with rain, then what is it there for? (For the sake of trivia.) Thanks in advance.