The whole thing is still suspicious: it was delivered to everybody whereas if it was supposed to be used only by the users who are aware of it, as now Mozilla tries to spin it, i.e. only to those who decided to "play the game", then the hidden install, especially to every user, was unnecessary as the normal extensions to Firefox are easily installed by the user, a click or two are enough:
https://addons.mozilla.org/en-US/firefox/addon/tabby-cat-fri...
