Developer's DescriptionBy Frank YanRe-size Firefox tabs to the width of a favicon.Making a tab into an app tab moves it to the left side of the tab bar and shrinks it to the size of its favicon.App tabs can be created by right-clicking a tab and selecting "App Tab", ctrl+clicking the tab (this shortcut can be customized), or dragging a tab to the region of existing app tabs.Likewise, app tabs will return to being normal tabs if you ctrl+click an app tab or drag it to the region of normal tabs.