Windows in Germany are really awesome
Turning the window handle 90° allows the window to swing inwards.
With the handle in 180° position or a port it is then able to tilt open.
The advantage of having a tilt window is that you can control the ventilation in the room. It allows the hot air to quickly escape through the top portion of the window and then also cut the strong breeze into the room.
Tilt and turn windows are the norm in Germany and many other northern European countries.