The Favorites tab shows one or more lists that have been marked as a favorite. To mark a group or a list as a favorite, select it, right-click to open the context menu and choose the Is Favorite option. You can make any repository node or any of your lists a favorite to display it in a separate tab accessed via the Favorites tab.
The Favorites tab can be displayed by pressing Shift + F8 or by using the Tabs command on the ribbon. By default the Favorites tab always contains the Last Opened tab.
When a particular object type is made a favorite, you can use the Toggle current view to toggle the Favorites tab between alphabetic grouping, grouping in dropdown and all objects: