Extras is a set of customizable KShutdown actions (commands).
Since version 3.0 Beta 5 this feature is available in all KShutdown versions (not only in KDE).
Click the Add or Remove Commands menu item to open default file manager (e.g Dolphin).
Now you can use your file manager to add/edit/remove links or folders.
Use file Properties to change icon, name, or the program you want to launch.
Note: The below list may vary depending on KShutdown version/build
and your Operating System.
*.lnk) - An application link (shortcut) created using Linux file manager or Windows Explorer
*.sh) - A valid script file with the "executable" attribute set
See the README file.
To launch an extra command from the [Command Line], use the
option with a file argument (you can use any supported file type).
kshutdown --help for more info.
kshutdown --extra "/full/path/to/myscript.sh"