I maintain a thingy written in C# that does cool things with keyboard backlights on System76 machines in Linux. Like make the left-third respond to CPU usage, right third blink when you have unread notifications, etc. The biggest one was turning off the keyboard when the screen blanked[1]. Almost all of the fun stuff requires native interop.

1: https://withinboredom.info/blog/2019/11/26/detecting-if-a-sc...