Mozilla says, "Add-ons installed through the official Firefox Add-ons site undergo a rigorous review process before they are published. These add-ons are verified and signed." Is that true or not? When I install "Desktop by Default" and "Desktop Mode Add-on" through the official Firefox Add-ons site, I get a warning saying they are unsigned. Why are they unsigned when they say they won't put anything on the official site that are unsigned? Has anyone even found an actual "signed" addon? I can't remember ever finding an addon that did not have that warning, on their official site.