Sections in the outer sealing of the windows

The window has two seals. One that can still be seen from the outside when the window is closed and one in the middle of the frame. The outer seal appears to be somewhat thicker and more robust than the one in the frame. Only the outer seal has the cut parallel to the frame, about 7cm.

My crystal ball says the window has a third seal, namely in the sash on the room side.

My crystal ball says the window has a third seal, namely in the sash on the room side.

The crystal ball is correct. But what is it now? Pressure equalization or (unwanted) forced ventilation?

The crystal ball is correct. But what is it now? Pressure equalization or (undesired) forced ventilation?

If no gaps/holes/breaks/... or rebate vents(?) can "interrupt" the middle seal and the inner stop seal, it can only be a pressure equalization that has nothing to do with ventilation. Notes: Quite a few laypeople/"experts" do not recognize "rebate vents"... this is especially the case with the new models of a manufacturer. Unfortunately, rebate vents are also often installed incorrectly (= not according to manufacturer instructions)... for example, there are too many large seal cutouts or the opposite...