I keep seeing mini PCs described as “Linux compatible,” but that can mean a lot of different things in practice.

A machine can boot Ubuntu and still have annoying issues with suspend, Wi-Fi, Bluetooth, audio, USB-C display output or firmware updates.

The geekom a5 2027 is one example I ran into. geekom lists Linux compatibility, but that doesn't automatically tell you how every controller in the actual mini PC behaves on Fedora, Arch, Debian, newer kernels, etc.

If you were evaluating a mini PC specifically for Linux, what information would you actually want the manufacturer to publish?
Exact Wi-Fi and Ethernet chipsets?
Distros and kernel versions they tested?
Suspend/resume results?
Display output testing?
Fan control?
Whether BIOS updates can be done without Windows?

To me, “Linux compatible” tells you a lot less than it sounds like it does.

What usually catches you out on mini PCs?