also used, then any libvirt domain can be used. However in write
mode, only libvirt domains which are shut down can be named here.
+Domain UUIDs can be used instead of names.
+
Using this flag is mostly equivalent to using the C<add-domain> command,
with C<readonly:true> if the I<--ro> flag was given, and
with C<format:...> if the I<--format:...> flag was given.