They never intended to show anything to the right of the doorframe on TV, so there's a random sign on the wall and a big hole in the wall (which makes sense if you are a camera crew wanting to film a sitcom in the apartment, that doesn't make so much sense in the fictional world that anyone would have a big rectangle cut out of the wall between their apartment and the hallway).

This post explains it nicely, by showing the noticeboard they normally use to cover that camera hole (which looks like an unfinished window frame, missing its architrave): https://x.com/MattBaume/status/1661785600050233344

There's a window-hole in what should be an exterior apartment wall facing a hallway. Right side of the screen.

New York apartments rarely have holes in their walls opening to the hallway.

haha. Take a look at the massive unfinished window into the hallway =).

I think it is the open hole in the wall next to the door -- which no real apartment would have. I think that part was meant be cropped in the final frame, maybe?

There's a cut out on the wall for cameras on a different angle.