Firefox was an innovation compared to IE, but it was explicitly a trimmed-down version of Mozilla, which had existed in the form of Netscape going back what amo

Firefox was an innovation compared to IE, but it was explicitly a trimmed-down version of Mozilla, which had existed in the form of Netscape going back what amount to geologic eras in terms of the history of the Web. Firefox's innovation wasn't the rendering engine, per se, but everything surrounding it, including add-ons.