/usr/share/doc/libscalapack-mpich-dev/changelog.Debian.gz is in libscalapack-mpich-dev 2.0.2-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libscalapack-mpich-dev/../libscalapack-mpich2.0/changelog.Debian.gz