Alfred Firefox
Ensure the Alfred workflow is installed and run it to register the native component with Firefox. (Don't worry if you receive a “No Connection to Firefox” error.)
After you've run the workflow in Alfred, open this extension menu again to reconnect.
This extension is the “backend” for the Firefox Assistant workflow for Alfred 4+. It enables you to search Firefox’s bookmarks, history, downloads and tabs from Alfred.
It doesn't do anything without the workflow.