I didn’t see it at first either. The spots of light on the floor also look like they could be reflecting off a transparent surface suspended at the level of the brown stripe on the wall.
Also, to me at first, the hallway looked much wider than it actually is thanks to the reflectiveness of the walls







Brave and Vivaldi have built-in ad blockers. Brave’s is based on uBO; Vivaldi’s is based on ABP.