This Firefox guide on how to make your first web extension is a good starting point to learn about the WebExtensions API. The first guide covers the basic directory structure, and how to debug the extension by sideloading it into the browser. Links to related documentation can be found on the Sidebar to the left.
We recommend using Firefox Developer Edition while developing the extension. We don't mind if you also test it on versions below Firefox 56, but our main aim is to support version 57+
Most console.log messages have been commented out rather than removed. So you can simply uncomment them to get suitable console output that will let you track the content of the variables as well as the flow of the program.
Fork the repository, make changes and commit them to your fork, and then send a PR this repository's master branch.
Please follow good commit message guidelines as listed in this blog post. A message body isn't necessary every time, but ensure that the subject itself remains in the imperative.