Unfortunately there doesn't seem to be a way to get this to run in the address bar, so that'll have to be changed in Firefox itself: https://bugzilla.mozilla.org/show_bug.cgi?id=433972
In order for this to do anything, you'll have to make
Alt the keyboard modifier rather than control: in firefox preferences
17 (control). You'll also have to disable the
ui.key.menuAccessKey which is by default set to
18; change it to something like
9999. In order for this change to apply, you'll have to restart the browser, which makes using this with
web-ext hard. Did I ever have this working?