Bio-Formats is a Java library for reading and writing data in life sciences image file formats. It is developed by the Open Microscopy Environment. Bio-Formats is released under the GNU General Public License (GPL); commercial licenses are available from Glencoe Software.
A "Formal JSON schema yet to be determined" as stated: https://github.com/ome/bioformats/blob/8bcb3c316ec9eb6fa42a8443287bb4b4f92c13e4/components/formats-bsd/src/loci/formats/dicom/DicomJSONProvider.java#L50-L52
Why not the DICOM JSON Standard itself? https://dicom.nema.org/medical/dicom/current/output/chtml/part18/sect_f.2.html