This add-on is dropped by installers distributed at http://softango.com (for example, http://softango.com/mozillacookiesview.html). The add-on doesn't do anything obvious, be it is installed silently (bypasses the opt-in dialog) and has been the cause of frequent crashes in the past.
We don't know much about what the add-on does because it is mostly binary. It doesn't appear to change any settings, so there's no problem there.
Just managed to get infected with this again and it did show about:newaddon this time.