Access Crowd HTML output results

I'm creating a website using the Crowd HTML Elements that let users/workers annotate images with the bounding box format. The form looks like this:

<crowd-form>
  <crowd-bounding-box
    name="annotatedResult"
    labels="['Referee', 'Player']"
    src="https://s3.amazonaws.com/cv-demo-images/basketball-outdoor.jpg"
    header="Draw boxes around each basketball player and referee in this image"
  >
    <full-instructions header="Bounding Box Instructions" >
      <p>Use the bounding box tool to draw boxes around the requested target of interest:</p>
      <ol>
        <li>Draw a rectangle using your mouse over each instance of the target.</li>
        <li>Make sure the box does not cut into the target, leave a 2 - 3 pixel margin</li>
        <li>
          When targets are overlapping, draw a box around each object,
          include all contiguous parts of the target in the box.
          Do not include parts that are completely overlapped by another object.
        </li>
        <li>
          Do not include parts of the target that cannot be seen,
          even though you think you can interpolate the whole shape of the target.
        </li>
        <li>Avoid shadows, they're not considered as a part of the target.</li>
        <li>If the target goes off the screen, label up to the edge of the image.</li>
      </ol>
    </full-instructions>

    <short-instructions>
      Draw boxes around each basketball player and referee in this image.
    </short-instructions>
  </crowd-bounding-box>
</crowd-form>

The results of a worker's submission looks like the following:

  {
    "annotatedResult": {
      "boundingBoxes": [
        {
          "height": 3300,
          "label": "Dog",
          "left": 536,
          "top": 154,
          "width": 4361
        }
      ],
      "inputImageProperties": {
        "height": 3456,
        "width": 5184
      }
    }
  }
]

I'd like to take this output and write it to a database, pass it to AWS Lambda, store it as metadata, etc. but I don't know how to access the results. Is the JSON output a property of some HTML DOM property I can grab?

I can attach a javascript function to the submit action of the crowd-form portion...

<script>
  document.querySelector('crowd-form').onsubmit = function() {
      ???
  };
</script>

...but I'm not sure what object I need to grab to get the results.

You can access the bounding boxes during the onsubmit event like this:

<script>
    document.querySelector('crowd-form').onsubmit = function(e) {
      const boundingBoxes = document.querySelector('crowd-bounding-box').value.boundingBoxes || document.querySelector('crowd-bounding-box')._submittableValue.boundingBoxes;
    }
</script>

Here's a working jsfiddle.