It works with composite manager like picom

Hmm. So it appears that CrossOver is dependent on a compositor being present. We should probably leave a note about this somewhere.

(I found this blog post to be very helpful.)

Just i3 does not have bundled compositor. Heavy environments like KDE/Gnome have it out-of-box. Yea, it would be good to mention it somewhere in README maybe.

I'm a Linux novice, is this something:

• I can manually install when the user runs the app
• could I test for it and display a link to it
• Add it to the readme

[...]Manually install when the user runs the app

You could, but I (and many others) would consider it somewhat invasive. It's also somewhat out of the scope of CrossOver, and it would add extra weight to the binary. If you take this route, you're essentially adding yet another system service.

[...]Test for it and display a link to it

There are a few ways to test if one is present. I recommend linking to the README section on Linux graphics; I sent a PR a few weeks ago to make a note of compositors in that section.

Add it to the readme

Already done, see #252.

Thanks, I opened a ticket with I3 about it: i3/i3#5522