This command is probably the vestigial remnant of a planned function that wasn't implemented. A token is set aside for it, but the command doesn't actually do anything, and will cause an error if you try to use it. It's not accessible through any menus, though, so that's okay.
The only potential use is to save on memory if you ever need to display "PrintScreen" somewhere - you can display this token instead.
- ERR:INVALID is thrown when trying to use this command.