I have a quest 2 that I burned sunspots into that resulted in blotches of pixels stuck on yellow. I use my headset for hours at a time and never notice them unless brought to an all black loading screen, and even then it's not a guarantee. The brain is crazy good at filling in blindspots.
It's empty space, and the whole row goes completely black in most fullscreen cases too as the screen is 16:10 BELOW the menu bar.
You forget it as easily as you forget that you have a nose right in the middle of your vision.