Safety Mod Pass Through to Truck Window

I haven't seen this done in years... like since the 80s. I think it's a misnomer to call the window above the step to the cabover a "pass through" window.

The window in my Arctic Fox is so small, only a very skinny could could fit through, and that wouldn't even work because the windows does not line up with the truck slider, if my truck even had a rear slider.