Process for creating a new template in qubes-builderv2

[Skyler]

Hello,

I am trying to use qubes-builderv2 to create a template for a new distribution. I am struggling to understand how to do this and hoping that somebody here can provide me with some guidance. There a few specific points that I would appreciate clarification on as well as a more general question.

Specific points:

- In the builder, there are a number of references to a chroot environment. I currently believe that the chroot is used for building packages in the target format. Is there also a chroot environment where the filesystem representing the template is prepared?
- In the update_parameters method of TemplateBuilderPlugin, the Debian and Fedora templates have 4 dependencies, 3 plugin dependencies (chroot, source, and build) and one component dependency. However, Gentoo only has a component dependency. Is this because the plugin dependencies are not relevant on Gentoo or because Gentoo is a less mature template?
- What output format does the builder produce when building templates? In case it is an RPM package, what is the package expected to contain?

General question:

Is there a good entry point for understanding the mechanics of how the builder creates a template? I have been looking at the code, but without the context of the overall process I am finding it difficult to understand the purpose of some of the things I read.

Thanks,
Skyler