By "information" you mean the idea that a screen brightness can be adjusted? I am honestly confused if you thought before reading this that pixels were somehow limited by how dim they could get?
This is not just the backlight setting: below a certain level the feature will darken the level of the pixels so that white (255, 255, 255) is reduced to something darker. On an OLED screen, of course, this just has the effect of allowing lower brightnesses than the phone's minimum, but on backlit screens it still has a surprisingly large effect.
