/usr/lib/x86_64-linux-gnu/libKF5GrantleeTheme.so is in libkf5grantleetheme-dev 16.04.3-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libKF5GrantleeTheme.so.5
/usr/lib/x86_64-linux-gnu/libKF5GrantleeTheme.so.5