This is a tool to monitor your network connection. It can check it doing requests to the desire server and with the desired interval, if it fails, it shows you a notification about that and also writes it in a log, the same happens if the connection is back or if your ISP changes your public IP.
Furthermore, it shows you the current latency in the extension's icon or shows 'off' if the conection is down. You can also track the latency in an useful graph that you can view if you click in the extension's icon.
Finnaly, you can see your public IP and monitor the changes in it :-)