/usr/lib/x86_64-linux-gnu/libsuperlu.so.5 is in libsuperlu5 5.2.1+dfsg1-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libsuperlu.so.5.2.1
/usr/lib/x86_64-linux-gnu/libsuperlu.so.5.2.1