This command (shortcut: Ctrl+g) is enabled in Text View and Grid View. It pops up a dialog (screenshot below) in which you can enter the line number and character number to go to. In Text View, the cursor will jump to the position you entered. In Grid View, the node closest to the line and/or character number you entered will be highlighted.
This feature is useful when you need to quickly navigate to a location, for example, when the location of an error is given in an error message.