Adds mouse gestures like Opera 12.

** Gestures (Right Click +)

Left: Go to previous page in history
Right: Go to next page in history
Up→Left: Go to parent directory
Up→Down: Refresh page
Up: Stop loading
Down (w/ link): Open link in a new tab
Down (w/o link): Open a new tab
Down→Up (w/ link): Open link in a new background tab
Down→Up (w/o link): Open a copy in a background tab
Wheel: Switch active tab
Down→Right: Close current tab
Down→Left: Minimize window
Up→Right: Maximize window
Right→Up: Restore recently closed tab/window (Extra Function; disabled in default)

** Permissions

Access your data for all websites: Required to enable gestures on each websites. (This is the most important permission.)
Access recently closed tabs: Required to restore recently closed tab (Right→Up).

** Notes

Developed for Firefox Quantum (version 57+), there is some restriction on legacy Firefox.
Not available on "about:" pages, PDF pages and etc. due to WebExtensions restriction.
Not available on AMO sites and some web pages due to the site restriction.

** Problems

A context menu pops up if gesture ends on child frame.
(Touch) Gestures don't work on child frames.
(Touch) Single tap and pinch zoom sometimes don't work. Then, you can emulate click by double tap.