keras/src/saving/saving_lib.py/_serialize_model_as_json
def _serialize_model_as_json(model):
    with ObjectSharingScope():
        serialized_model_dict = serialize_keras_object(model)
    config_json = json.dumps(serialized_model_dict)
    metadata_json = json.dumps(
        {
            "keras_version": keras_version,
            "date_saved": datetime.datetime.now().strftime("%Y-%m-%d@%H:%M:%S"),
        }
    )
    return config_json, metadata_json