The new Shodan Firefox Add-on is now out.
You can get it directly from Mozilla or on Github in the release section.
If you have any feedback regarding the add-on, feel free to ping us on Twitter: @romainletendart and @PaulWebSec. If you find a bug, create an issue on Github and/or submit your pull request. It will be later on pushed on Mozilla website.
Simply use web-ext.
This add-on has been released under MIT License.