Are placeholders possible in api.yaml for config pipeline in AEM as a cloud service?

Hi all,
we are registering API client ID’s in an api.yaml (see https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/implementing/developing/open-api-based-apis) and deploy them with a config pipeline.

The documentation describes that for secrets can be used placeholders (see https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/operations/config-pipeline)

 Something like shown here seems not to work:
 

kind: "API"
version: "1"
data:
  allowedClientIDs:
    author:
      - "${{MY_AUTHOR_CLIENT_ID}}"

We added the values as secrets with “Service Applied: All” in cloud manager configuration but it only works with specific values directly in the api.yaml.

Do you know if this not supported kind: API?

Best,
Mark