/usr/lib/x86_64-linux-gnu/libsonic.so is in libsonic-dev 0.1.18-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libsonic.so.0.1.18
/usr/lib/x86_64-linux-gnu/libsonic.so.0.1.18