Netmon

Network monitor - see requests and responses, including the HTTP headers, of the current page, or globally.

You can use it at any time, also *after* the page has loaded.

This is useful when there are random errors in some cases and you just want to see what happened, list the past requests.

It also constantly displays current count of requests in any given tab.

And - it's open source: https://github.com/kpion/netmon

If you have any suggestions, please don't hesitate to reach me on [email protected] or file an issue on the github page above.