Rated 5 out of 5 stars
Version 1.90 available, says its Works with Firefox 2.0 - 13.0a1 but install rdf in xpi says max Firefox version 12.01.
In order to make it work open xpi with Winrar, Edit install.rdf and change this line for Firefox to "maxVersion>16.*"
Save, then Delete META-INF Folder ( Otherwise Firefox will not let you install the modified xpi) Save and install.