The "Funnelcake" builds were special builds put out to help understand about how people downloading and installing Firefox builds. Its the same as the regular Firefox, the only thing it the "funnelcake" does is allow us to measure how many of the downloaded installers hit the first run page and subsequently check for updates. There is no personalization or user data involved. See this thread for some more details: https://support.mozilla.org/en-US/questions/931860