Are you asking about MPICH_MPIIO_HINTS_DISPLAY? That should display the hints at file open.
> man intro_mpi
MPICH_MPIIO_HINTS_DISPLAY
If set, causes rank 0 in the participating communicator to
display the names and values of all MPI-IO hints that are
set for the file being opened with the MPI_File_open call.
Default: not enabled.
The MPICH_MPIIO_HINTS is used to set hints.
> MPICH_MPIIO_HINTS_DISPLAY=1 MPICH_MPIIO_HINTS=*:romio_no_indep_rw=true ....run a program
PE 0: MPIIO hints for testdir/file:
...
cb_nodes = 1
romio_no_indep_rw = true
cb_config_list = *:*
romio_filesystem_type = CRAY ADIO: