It is an integration with [CGMZ] Controls Window, which is a plugin that can add a window to any scene that shows the player what keyboard/gamepad controls do what in the scene depending on the player's last input type.
If you want to set one up you just create a preset in that plugin and then type the preset id in to my plugins that integrate with it. Otherwise you need to tell it the scene constructor which isn't always easy for people to find if they don't know how to read JS code.