/usr/lib/x86_64-linux-gnu/libvirt.so is in libvirt-dev 1.3.1-1ubuntu10.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libvirt.so.0.1003.1
/usr/lib/x86_64-linux-gnu/libvirt.so.0.1003.1