/usr/lib/x86_64-linux-gnu/libmirclient.so is in libmirclient-dev 0.31.1-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libmirclient.so.9
/usr/lib/x86_64-linux-gnu/libmirclient.so.9