Provides ability to go back/forward through tabs. In other words, when you cannot go back anymore by the "Back" button, then this Firefox will focus to the owner (opener) tab of the current tab (and, the "old" current tab is possibly closed.) For "Forward" button, Firefox focuses to the suitable "next" tab if possible.
Those navigations work more intelligently if Tree Style Tab is installed.
Similar or Related Extensions
I don't move focus of tabs, I want to do Back and Forward simply.
Tab History provides ability to clone session histories of the owner tab to tabs opened from there.