When Spock first brings Mudd and the women to Kirk’s cabin, he is writing on the desk and next to him we see the wall. I have been watching the episode tonight, and it appears to be a window, perhaps one of the early season one ideas that was later removed?
Is anyone able to confirm this? Or is it a picture?
Is anyone able to confirm this? Or is it a picture?

)
But I digress,
). Keep it simple, they're just maintenance hatches to get at that stuff, if needed. Later, removable decorative wall panels were added to hide them. Also note that these decorative wall panels are in all the quarters.
Easy-Peasy. 