if u have good ground affects it will suck air from the engine bay so opening that back strip will draw air in, if the engine bay is poor airflow and going positive pressure then it will suck air in from that rear bonnet opening, then also the point the airflow hits that bonnet to windscreen angle will either flow or create a pressure spot depending on speed of airflow, interesting to see whats going on
Yeah the base of the windshield is a high pressure spot on most cars, which is why cowl induction works. But like the video mentioned, you do have to duct it to the engine air intake. If you don't you are just increasing the pressure under the hood, which causes lift. The higher underhood pressure also reduces the pressure delta across the radiator, etc. at the front of the car, which ends up hurting the cooling capability.
My car is missing the rear hood seal, it's on my list of things to replace.