docs: def data_json(self, extra_context=None, publish=False):
          """
          Serve site context as JSON. Useful for debugging.
          """
          if not self.project.CREATE_JSON:
              # nothing to see here, but the right mimetype
              return jsonify()
  
          if not self.data:
              # this sets site.data by spreadsheet or gdoc
              self.get_context(publish)
  
          return jsonify(self.data)