First of all, thanks for this addon.
For me the arrow have an unespected behaviour with Firefox Quantum, and I hope this addon will allow to customize the action performed by the arrow.
With firefox Australis (and previous ones) I was accustomed to use the arrow of an already loaded page to duplicate the page and reload it with a comfortable single click. It behaves in this way because I setted Firefox to open a new tab when I type and send something in the address bar.
It seems that Firefox Quantum don't open a new tab if the address is the same of the current page, converting the expected behaviour in a simple reload.
Four stars because the addon is fine, but I can't have my old way to use it back again.

U cant CUSTOMISE the position of the button... that is very lazy of the developer

[Edit]: Well in this case Job well done, id say the only thing left to do is an option to give it a color since the black and white doesnt really stand out...

36e5a0

excellent work, thanks!
now works in Firefox 57