Which type of file to return for the plan: PDF, or CAD for DWG and DXF files. A plan without a file of the requested type returns its latest file of the other type.
When omitted, the plan's latest PDF file is returned, and a plan without a PDF file is not found.

The HTTP Request-Id request header is an optional and unofficial HTTP header, used to trace individual HTTP requests from the client to the server and back again. It allows the client and server to correlate each HTTP request. If not provided by the client, the server should generate a unique request ID and include it in the response.