/usr/lib/x86_64-linux-gnu/libQt5Purchasing.so is in qtpurchasing5-dev 5.6.0~git20151023.2f454143-0ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libQt5Purchasing.so.5.6.0