text: {
      browser.browserAction.onClicked.addListener(() => {
          // FIXME: implement this. Requires storing global state for each
          // window as there is no API to check whether the sidebar is opened.
          let isSidebarOpenedInCurrentWindow = false;
          if (isSidebarOpenedInCurrentWindow) {
              browser.sidebarAction.close();
          } else {
              browser.sidebarAction.open();
          }
      });
  }
  