If you have more than one copy of React DevTools installed and enabled (e.g. the version in the Chrome store and a locally built version) they can interfere with each other.

DevTools should detect this case and warn by showing a dialog in the DevTools UI and/or by logging to the console.

Note that we _should not warn_ if a related tool like Fast Refresh is present, only another copy of DevTools.
}
    case 'internal': {
      
      
      
      
      
      checkForInstalledExtension(LOCAL_EXTENSION_ID).then(isInstalled => {
        if (isInstalled) {
          callback(true);
        } else {
          callback(false);
        }
      });
      break;
    }
    case 'local': {
      if (__DEV__) {
        
        
        
        callback(false);
        break;
      }
      
      
      
      
      console.error(UNRECOGNIZED_EXTENSION_WARNING);
      chrome.devtools.inspectedWindow.eval(