How to use Browser Experiement when creating a web extension?

  firefox-webextensions, javascript

I want to know how I used the UrlBar Browser Experiment on Nightly builds for a personal extension that opens a new tab to a specific page but clears the address bar (URL bar).

If someone could help me figure out how to do this or figure out what I am doing wrong already, that would be very helpful!

Source: Ask Javascript Questions