/usr/lib/x86_64-linux-gnu/libunity-gtk3-parser.so is in libunity-gtk3-parser-dev 0.0.0+18.04.20171202-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libunity-gtk3-parser.so.0.0.0