/usr/lib/x86_64-linux-gnu/libQGLViewer-qt5.so.2.6 is in libqglviewer2-qt5 2.6.3+dfsg2-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libQGLViewer-qt5.so.2.6.3
/usr/lib/x86_64-linux-gnu/libQGLViewer-qt5.so.2.6.3