Hi,
this updates us to the recent version 1.4.1
Ubuntu has a delta that - by the virtue of different policykit/permission handling - isn't needed by Debian.
But it would help a lot to get it accepted and via dpkg-vendor --derives-from Ubuntu we can do so while keeping it a no-op for you.
dpkg-vendor is usually always present since we have debhelper-compat=12 => debhelper => dpkg-dev.
Let me know if you'd want to see that expressed as an explicit depends in d/control
Attached is a build log in unstable amd64: libvirt-dbus_1.4.1-1_amd64.build