Those must not be units with any meaning, then; my Librem15 can get pretty bright, but the numbers only go from 1 (all the way off) to 47 (dimmest) through 20 steps to 937 (brightest). It would be interesting if the monitor could be calibrated so that outputs lumens...

By the way, to change them on my keyboard I press Fn-F5/F6 (the symbols are on the keyboard), so it goes to show there is not really a standard placement aside from 'out of the way'. GNOME also has a brightness slider.

—Arlo