Pretty good, but there are few improvements to be made.

1.) I'd like to use the same gesture to open a new empty window(s) and to open a link to a new window (if starting gesture from link). At the moment this is not possible with Gesturefy, since it can only be done if using tabs and I for example would like to use several browser windows instead of tabs.

2.) It would be nice to be able open pictures to a new window when starting new window/tab gesture above them. Just like if they were links.

Both of these were implemented on All-in-one-mouse-gestures that is not working with new Firefox anymore and I'm trying to find replacement to it. Gesturefy is close, but not quite. These features should not be limited by Webextension API, so I'm hoping and praying that you update Gesturefy with those.