Q: How add keyboard shortcut for "show desktop" in Xubuntu 20.04? In Xubuntu 20.04, I can't find a keyboard shortcut for "show desktop". For example, Ctrl+Alt+D does nothing. Of course I can define a new keyboard shortcut. The problem is I don't know what program performs a "show desktop".

A: This solution has been tested in Xubuntu 20.04.1 run as Live USB.
To check and/or change the keyboard shortcuts for "Show Desktop" feature, go to:
Settings -> Window Manager -> Keyboard tab
and look for "Show Desktop" item. Pressing the "Edit button" you can configure a new keyboard shortcut.
Below, an image as reference.

