WebCrypto tracer for Chrome

One of our interns recently put together a Chome extension that traces calls to the WebCrypto API. A dropdown gives a list of all key objects in the session and their attributes.
You can get an output file in JSON format giving all the calls to the crypto API the web app made together with their parameters, or a list of the key objects.

There some screenshots at http://cryptosense.com/webcrypto-api-tracer/

The code is on Github under BSD license https://github.com/cryptosense

Feedback welcome!

Graham Steel