For the functions installing addons, you need to create a folder "extensions" from where you run the django project and place there the XPIs. The Extension needs to have the name of its install.rdf file.
Currently they are:
Things, that will not be included:
- Some cool addons. The addons list should be short and mostly privacy addons.
- Your favourite performance setting. It's not the scope of the project and not all people need the same performance settings.
You're welcome to create an own profile for such settings or fork the whole project.