Cool project. It might be interesting, to the HN crowd at least, to see blog post or other writeup on the specific mods you made to Gecko and other standard browser components to create this.
Thanks, we are trying to write more blog posts since we're cutting into new territory. "Customizing Gecko" would be a fun one. I definitely stared at the Waterfox repo at few times (https://github.com/mralex94/waterfox).