Output Format
A target serialization format. Each named instance carries a `backendUri` that the runner uses as a registry key to find the IDocumentAstBackend that knows how to serialize a docast.Document to that format's bytes.
A target serialization format. Each named instance carries a `backendUri` that the runner uses as a registry key to find the IDocumentAstBackend that knows how to serialize a docast.Document to that format's bytes.