There’s a proposed json format file in this PR ENH: Machine-readable definitions by wtclarke · Pull Request #9 · wtclarke/mrs_nifti_standard · GitHub. Do you think that you will be able to use this file in Osprey?
Yep, it’s done (see Update NIfTI-MRS validation · schorschinho/osprey@926f389 (github.com)). I think this should make every Osprey-written nii/nii.gz file fully compliant (until someone finds the next bug, of course!).