ONNX model input variables

Question

I've been tasked with writing a scoring consumer for any ONNX model that I'm given. When looking over the ONNX model format I do not see anywhere that defines the input variables in the model. For example, after creating a model with the iris dataset, I see the input is defined as a float array of 4 values but it does not specify which variable goes with which input value. Is there anywhere in the saved model that tells a consumer of the model which variable needs to be in which array index or does the producer of the model have to tell the consumers what order they need to be in?

Thanks.