/usr/share/doc/libhdf5-mpich-dev/changelog.Debian.gz is in libhdf5-mpich-dev 1.8.4-patch1-3ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libhdf5-mpich-dev/../libhdf5-mpich-1.8.4/changelog.Debian.gz