Don't show the screenshot flash when a screenshot is being sent to the clipboard, as opposed to a permanent file, matching the behaviour of a well-known OS. This is possibly useful if your laptop happens to have a dedicated PrtSc key in the bottom row of the keyboard, and you usually happen to like that function, but do not wish to flashbang your eyes if you press it accidentally. Use version 1 of this extension for GNOME Shell 3.28.