/usr/lib/x86_64-linux-gnu/libunity-settings-daemon.so is in unity-settings-daemon-dev 15.04.1+18.04.20180413-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libunity-settings-daemon.so.1.0.0