I got a new laptop. More on that later, perhaps.
This laptop doesn’t have hardware controls for the screen brightness, it’s done via software. In linux, this is done via poking at stuff in /sys.
So to make my life easier, I wrote a little Python script to do it in a sane way. I do a similar thing for the keyboard backlight, but that only has 3 levels of brightness, so the math is much easier.