Awesome add-on. Missing this when transitioning from chrome to firefox was painful. I had to use 2 different extensions to have half the functionality. One to ALT+Z to previous tab, and another to show and navigate tabs, in recent order! Most extensions don't show them by recent order.
The navigation shortcuts are great for my use case. ALT+Q to open list, ALT-W to select and switch tab without having to press enter, and ALT+Q again to close list (because sometimes I change my mind), all of that without having to lift my fingers to reach for ESC key.
Finally, fast and productive tab switching, thanks so much.