Eclipse Hydra is a fork of Basilisk made for Windows XP. Some advantages over upstream and roytam1's Serpent are more optimizations and better interoperability with upstream. (using SQL storage intead of DBM)

By the way, this browser replaces r3dfox classic as it makes no sense for me to build two browsers so similar. I would be better off working up to Waterfox Classic capability rather than trying to get it working on XP.

Main download link (GitHub)

Alternative download link (SourceForge)

Installer and true portable varaints
More optimizations than upstream
Features from Mypal like duplicate tab
Experimental e10s support
Uses SQL instead of DBM for better compatibility with upstream profiles.
JPEG XL support