docs: public static byte[] saxonTransform(Map<String, byte[]> files, byte[] source, byte[] xslt) throws TransformerException  {
      TransformerFactory f = new net.sf.saxon.TransformerFactoryImpl();
      f.setAttribute("http://saxon.sf.net/feature/version-warning", Boolean.FALSE);
      StreamSource xsrc = new StreamSource(new ByteArrayInputStream(xslt));
      f.setURIResolver(new ZipURIResolver(files));
      Transformer t = f.newTransformer(xsrc);
   
      t.setURIResolver(new ZipURIResolver(files));
      StreamSource src = new StreamSource(new ByteArrayInputStream(source));
      ByteArrayOutputStream out = new ByteArrayOutputStream();
      StreamResult res = new StreamResult(out);
      t.transform(src, res);
      return out.toByteArray();    
    }