xe vm-param-get param-name=networks uuid=<vm_uuid>
Works great for me, both with LVM SR and ZFS file SR!
Just one minor issue: I can't get an old Windows XP VM to boot with Citrix legacy PV drivers. It was working with xcp-ng 7.6, but no longer with 8.0 beta. It does not have internet access, It is needed to control old hardware for which no driver for newer Windows OSes exist.