i’m pretty sure he’s referring to those physical lights embedded below/around the projector screen in some theatres that’re sometimes left still on, but very dimmed. i’m not a cam guy but i’d imagine if you do watch cams it’d be kind of annoying the whole entire time to have them on screen.
yeah i mean idk i have no idea lmao. i just googled slot light and saw lights that looked vaguely similar to some local theatres i’ve seen around my country