code: private void updateDocTypesFromConfiguration() {
          resetDocumentTypesAndExtractors();
          JBakeConfiguration config = utensils.getConfiguration();
  
          ModelExtractorsDocumentTypeListener listener = new ModelExtractorsDocumentTypeListener();
          DocumentTypes.addListener(listener);
  
          for (String docType : config.getDocumentTypes()) {
              DocumentTypes.addDocumentType(docType);
          }
      }
docs: Iterates over the configuration, searching for keys like "template.index.file=..."
  in order to register new document types.