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.
};
          let debugIDCounter = 0;
          
          
          let fetchFileWithCaching = null;
          if (isChrome) {
            const fetchFromNetworkCache = (url, resolve, reject) => {
              
              
              let debugID = null;
              if (__DEBUG__) {
                debugID = debugIDCounter++;
                console.log(`[main] fetchFromNetworkCache(${debugID})`, url);
              }
              chrome.devtools.network.getHAR(harLog => {
                for (let i = 0; i < harLog.entries.length; i++) {
                  const entry = harLog.entries[i];
                  if (url === entry.request.url) {
                    if (__DEBUG__) {
                      console.log(
                        `[main] fetchFromNetworkCache(${debugID}) Found matching URL in HAR`,
                        url,
                      );
                    }
                    entry.getContent(content => {
                      if (content) {
                        if (__DEBUG__) {
                          console.log(
                            `[main] fetchFromNetworkCache(${debugID}) Content retrieved`,
                          );