The upstream fabric8 open source project is now focussed on the 2.x version based on Kubernetes.
JBoss Fuse versions 6.x includes its own branch of fabric8 1.x using Karaf and ZooKeeper.
So for any questions relating to fabric8 inside JBoss Fuse 6.x you are best off using one of these:
You can also browser the JIRA for JBoss Fuse
The JBoss Fuse fork of fabric8 1.x is here: https://github.com/jboss-fuse/fabric8