Hello David, Nadav.
This cluster is not related to the hook. This cluster was intended for the migration of hosts from Fedora to CentOS. This was unfinished because we have only one host in that cluster and at that time did not have any more baremetal to add as the second, so was not able to move VMs there from Production cluster. The plan was to add the second host as soon as it is available, then move VMs from Production there and then preocision Fedora hosts in Production with CentOS and essentially remove Production Fedora cluster.
Not sure if the plans for upgrades changes. If they are then you can take this of cause.