This tool simply hides the interface layer so you can view the map unhindered or take clean fullscreen screenshots. The interface will remain hidden until you hit Esc or right click. You can still pause/unpause and move the map around, so this is an excellent way to sit back and observe fortress life a little without being distracted by announcements or statistics.
Note that the interface layer and the map layer cannot be separated in ASCII mode. This script can only hide the interface in graphics mode.