<p>All this message means is that the automatic updates feature of <i>Tor Browser</i> has been disabled. This is done intentionally in Tails to make sure that no security feature or configuration gets broken by automatic updates of <i>Tor Browser</i>.</p>
The letterboxing feature of *Tor Browser* helps to prevent websites from identifying your browser based on the size of its window.Without letterboxing, websites could use the size of the browser window to track visitors or weaken your anonymity.
The letterboxing feature of *Tor Browser* works by adding gray margins to the browser window when the window is resized. The webpage remains as close as possible to the desired size without revealing the actual size of the window.
