/etc/default/xendomains on the hosts is not packaged
The default configuration of the /etc/init.
Each XVM host is currently configured to attempt to migrate VMs to the "next" host (e.g. arklay-mansion migrates to citadel-station, citadel-station migrates to aperture-science), and to never save VM state, but these changes are unpackaged.
Attached is the relevant patch for citadel-station (note that this is generalized for any host)