transpect/idml2xml ? reverse-engineered prompt

Build me a small library that can take an InDesign IDML file and convert it into Hub XML, and also let me extract the tagging information from the IDML.

I mostly want the core conversion logic, not a full app, so keep it focused on the library itself. It should be able to work with the IDML package structure, handle the relevant XML transformations, and include the supporting mapping files or catalogs if needed. Please make it easy to run and easy to extend later for more IDML edge cases.

If you need to check current XSLT or XML processing details online while wiring it up, go ahead. I’d also like a simple example or sample input and output so I can see how to use it and verify it works.