gnome-screenshot:tldr:faa8d

The gnome-screenshot command is used to take screenshots in the GNOME desktop environment. When you include the --clipboard option with the command, it takes a screenshot of the entire screen or a specific area (depending on the additional options used) and stores the captured image in the clipboard.

Instead of saving the screenshot to a file on your computer, the --clipboard option places it into the clipboard memory. This allows you to easily paste the screenshot into other applications, such as image editors, document editors, messaging apps, or emails, without needing to save it to disk and then manually attach or insert the image.

Basically, by using gnome-screenshot --clipboard, you capture the screen or a region and have the screenshot readily available to paste into other applications for immediate use.