Zirconium, but based on Freedesktop SDK instead of Fedora.
Zirconium Hawaii is a distribution that builds its own components in a manner that is both far closer to the source, and is 100% reproducible.
Zirconium Hawaii can be compared most accurately to Gnome OS, which is our biggest inspiration for this project. We use the same build system as Gnome OS, and we even use components from Gnome OS!
Currently, there isn't an official installation method. Rebasing from Zirconium (Fedora) to Zirconium Hawaii has been done successfully, but it is not officially supported, and will give you strange issues.