MDN will switch to a new design later today, a sneak peek: https://blog.mozilla.org/opendesign/mdns-new-design-beta/

FUEL is deprecated as of Firefox 40. Consider using the Add-ons SDK instead

This should be redrected to extIApplication.

Document Tags and Contributors

 Contributors to this page: teoli, Sheppy, LouCypher, Nickolay, jenzed
 Last updated by: teoli,