My main work laptop is a Thinkpad X1 Carbon running Debian 9, which usually works pretty well but I've also been procrastinating on getting it to run perfectly.
One thing I had forgotten to configure was the screen brightness keys with my
window manager i3. I had forgotten that I tried to configure it before, but got
stuck on some extremely unhelpful error messages from
this short blog post documents a workaround for the issue in case anyone else
has a similar setup.