Junit test metadata and api, source and source_type

When I query the API for test metadata:

curl https://circleci.com/api/v1.1/project/github/ACCT/project/12345/tests -H "Circle-Token: REDACTED"

I get back the results as I would expect and I can pipe that into jq and see our failure:

 jq '[.tests[] | select(.result=="failure")] | unique' ~/test.json
    "classname": "spec.features.admin.commerce.member_cards_spec",
    "file": "spec/features/admin/commerce/member_cards_spec.rb",
    "name": "Removing Stored Credit Cards with stored cards selecting a non-default card removing the card",
    "result": "failure",
    "run_time": 14.366128,
    "message": "Failure/Error: expect(page).to have_content(last4)...'",
    "source": "unknown",
    "source_type": "unknown"

Is there a way to pass along additional attributes from a junit formatter that I can get back in the API (e.g. team)? I tried adding additional attributes to our rspec junit formatter, but had no luck. It looks like there is source and source_type. I could use that but I am unsure where to set that in the junit output to get it to pass through, because it isn’t in the schema either.