/usr/lib/x86_64-linux-gnu/libQtXmlPatterns.so.4.8 is in libqt4-xmlpatterns 4:4.8.5+git192-g085f851+dfsg-2ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libQtXmlPatterns.so.4.8.6