/usr/lib/libkaddressbookprivate.so.4 is in kaddressbook 4:4.13.0-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/libkaddressbookprivate.so.4.13.0
/usr/lib/libkaddressbookprivate.so.4.13.0