Great! Rated 4 out of 5 stars

Extremely useful and easy to use. Can be used to create a toolbar button shortcut to any file, not just to executables. I used it to make a button for userChrome.css and one for Replay Video Capture. It will not, however, creat a shortcut to a folder.

Unfortunately, the buttons cannot be positioned separately on the toolbar. They all stay together. I'd give this 5 stars if separate positioning were possible.

This review is for a previous version of the add-on (0.11.1-signed.1-signed). 

Extension adds only space for buttons. You can move this space to any toolbar, but with all attached buttons together. I not plan separate positioning buttons.