Major Description
The layering feature in Daffodil needs a supported API.
We need to study the current layering implementations, and see if they can be further simplified, and then define an API we are willing to support longer term, even if better ideas subsequently come along, so that users/authors of schemas can at least depend on the API being solid from release to release.
I'm ok with this only being a Scala API. A Java API could be added in the future if needed.