Yep, the standalone Firefox browser's codename was Phoenix. I was also on it back in the day. From the Firefox Wikipedia page:

Firefox is the spiritual successor of Netscape Navigator, as the Mozilla community was created by Netscape in 1998, before Netscape's acquisition by AOL.[14] Firefox was created in 2002 under the codename "Phoenix" by members of the Mozilla community who desired a standalone browser rather than the Mozilla Application Suite bundle.