Goanna

Goanna as an independent fork of Gecko was first released in January 2016.

As the name (a group of carnivorous lizards most common to East Asia and Australia) might suggest, it is a close relative to the Gecko engine which it has forked off of, which in turn has been rooted in the "next generation layout engine" that has been part of the Mozilla group of products for many years. As such, it shares many features with Gecko, although it is not a perfect match in how it behaves or what tags it supports and in what way. Similarly, it provides the base framework for the XUL language specification which will be maintained in Goanna.

Goanna does not have a stand-alone source, since it can't be used as a stand-alone library. If you want to make use of the engine, you can build your application on the Unified XUL Platform (UXP). The engine is an integral part of that platform, the source of which can be found on Gitea.