/usr/share/man/man1/mdrun_mpi_d.mpich.1.gz is in gromacs-mpich 2018.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man1/mdrun_mpi.mpich.1.gz
/usr/share/man/man1/mdrun_mpi.mpich.1.gz