/usr/lib/x86_64-linux-gnu/libqxmpp.so is in libqxmpp-dev 0.9.3-1build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libqxmpp.so.0.9.3
/usr/lib/x86_64-linux-gnu/libqxmpp.so.0.9.3