Passage: January 1998 was also the month that Netscape started the open source Mozilla project. Netscape publicly released the source code of Netscape Communicator 4.0 in the hopes that it would become a popular open source project. It placed this code under the Netscape Public License, which was similar to the GNU General Public License but allowed Netscape to continue to publish proprietary work containing the publicly released code. However, after having released the Communicator 4.0 code this way, Netscape proceeded to work on Communicator 4.5 which was focused on improving email and enterprise functionality. It eventually became clear that the Communicator 4.0 browser was too difficult to develop, and open source development was halted on this codebase. Instead, the open source development shifted to a next-generation browser built from scratch. Using the newly built Gecko layout engine, this browser had a much more modular architecture than Communicator 4.0 and was, therefore, easier to develop with a large number of programmers. It also included an XML user interface language named XUL that allowed single development of a user interface that ran on Windows, Macintosh, and Unix.  The slogan for this open sourcing effort, "Free The Lizard", carried comedic sexual overtones.

Question: Mozilla was actual the product of what other notable web browser?
Netscape