This will now open a new tab with a list of all the tabs that are currently open in the browser and how much memory, each of these browsers is taking up on your system. This will give you a fair idea about the performance of the browser on your system and if you notice any of the tabs are occupying too much memory, you can immediately close them to make your browser and your system a lot more responsive.
If you want to try out this feature and many more surprise features on the Firefox browser, you can download a copy by clicking on this link.
