/usr/lib/liblightdm-qt5-3.so is in liblightdm-qt5-3-dev 1.10.0-0ubuntu3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/liblightdm-qt5-3.so.0.0.0
/usr/lib/liblightdm-qt5-3.so.0.0.0