/usr/lib/x86_64-linux-gnu/libQGLViewer.so.2 is in libqglviewer2 2.5.0+dfsg-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libQGLViewer.so.2.5.0
/usr/lib/x86_64-linux-gnu/libQGLViewer.so.2.5.0