TabletNav автор Shineblind

Switch tabs by swiping down a bar from the top of the screen and see them all as favicons, go back and forwad in history of the window and jump between tabs with the bottom left and right buttons (you can disable the bottom left and right buttons in options).

Made with touchscreens and tablets in mind like Surface Pros, especially useful if you have some other programs open on the same time as using Firefox because the top tabs get so narrow.