CloudWatch Events input transformers

Are CloudWatch Events input transformers supported?

The input block for cloudwatch events seems to supported only constant input or inputPaths (subsetting part of the actual event).

I would like to pass constant data alongside the actual event.

The documentation doesn’t seem entirely clear … the following (a) preserves the actual event, and (b) adds new fields to the detail object:

  - schedule:
      rate: rate(1 minute)
          version: '$.version'
          id: '$.id'
          detail-type: '$.detail-type'
          source: '$.source'
          account: '$.account'
          time: '$.time'
          region: '$.region'
          resources: '$.resources'
        inputTemplate: '{"version": <version>, "id" : <id>, "detail-type": <detail-type>, "source": <source>, "account": <account>, "time": <time>, "region": <region>, "resources": <resources>, "detail": { "tz": "America/Chicago", "dst": true } }'

Here is the event object, as passed to the Lambda function:

    "version": "0",
    "id": "3e3187de-58bd-bb7f-36af-aaba7df33719",
    "detail-type": "Scheduled Event",
    "source": "",
    "account": "...",
    "time": "2020-12-02T16:28:36Z",
    "region": "us-east-1",
    "resources": [
    "detail": {
        "tz": "America/Chicago",
        "dst": true