code: function () {
        let encoded = this.responseText;
        encoded = window.he.encode(encoded);
        codeViewer.mustache = encoded;
  
        if (codeViewer.tabActive === 'm') {
          codeViewer.activateDefaultTab('m', encoded);
        }
      }
docs: This runs once the AJAX request for the mustache markup is finished.
  If the mustache tab is the current active tab, it adds the content to the default code container.