/usr/lib/x86_64-linux-gnu/libhdf5_mpich.so is in libhdf5-mpich-dev 1.8.16+docs-4ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libhdf5_mpich.so.10.1.0
/usr/lib/x86_64-linux-gnu/libhdf5_mpich.so.10.1.0