The PO cut out the top panel of the cabin doors and added a plexiglass window. This lets a lot of light into the cabin, and also makes it safer because you can see if someone in the cockpit is in the way of opening the door. He did this to both fore and aft cabin doors.
I haven’t seen other boat photos showing anyone else having done this, so I thought I would share this good idea.
Note the window cut out area has a routed step on the cabin side of the door so that the plexiglass has a lip to be pushed against from the cockpit side. A good way to adhere the plexiglass in place against this lip with an adhesive tape, such as 3M VHB tape.
View from cockpit:
View from forward cabin