/usr/lib/x86_64-linux-gnu/libqsopt_ex.so.2 is in libqsopt-ex2 2.5.10.3-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libqsopt_ex.so.2.1.0
/usr/lib/x86_64-linux-gnu/libqsopt_ex.so.2.1.0