This issue tracks the release note for the following Fedora Change:

https://fedoraproject.org/wiki/Changes/FedoraWorkstationImageBuilder

This is a pretty minor change at present. It will just result in the existence of an alternative build of the Workstation live using a different build tool. This build will be pretty hidden, for Beta/Final release it may not really be discoverable at all. It was initially proposed as replacing the existing image, which would have been more significant (though hopefully still not end-user visible). Now it's a stepping stone on the way to that.