What happens when you press the F4 button?

I was programming my game, and accidentally pressed the F4 button. A lot things went white, although some things seems to retain their materials. I thought it looked great, I’m looking for a cartoon aesthetic and this seemed a good start. What did the F4 button do, exactly, to produce this?

Here are the before and after pics.

It’s the Lighting Only / Detail Lighting Viewport.
Afaik it does not work in Shipped Builds

Thank you. Is it the same as putting a white material on everything?

Yes. A white Base Color should do the trick