The administrator with ArchivistaBox is called 'root'. Consequently, to edit files with administrator rights via the desktop, the right mouse button can be clicked in Caja and the menu item 'Open as Admninistrator' can be called up.
There is a clear warning after the menu item is invoked.
Additionally the root password has to be entered.
In the title bar there is a subtle hint that root privileges are used.
Please note that improper editing of files can destroy the running system.