Install superkb by entering the following commands in the terminal:
sudo apt update sudo apt install superkb
Description:
Hotkey-based application launcher with on-screen hints
Superkb is a keyboard-based application launcher based on a hotkey (usually the Super key) that allows for on-screen keyboard hints to be displayed if the hotkey is held long enough without calling any bound action.
Homepage: http://superkb.sf.net/
Version: 0.23-2
Section: universe/x11