Unfortunately there is not. However, its pretty easy to watch the requests the extension makes using Chrome's debugger:
2. Make sure "Developer mode" is checked.
3. Click "Inspect views: background page" next to Mitro Login Manager
4. Click the network tab
5. Do something with Mitro. For example, click the popup, and click the Mitro logo in the lower left corner.
When I do this, I get ListMySecretsAndGroups in the Chrome debugger
Click on it, and copy the form data. This is the contents of the request. If you click the Response tab, you'll see the response from the server.
The structures that are sent and received are defined here:
The main server entry point is MitroServlet.doPost, which unwraps the first "outer" layer and ensures it is signed correctly, then calls the specific handler. This may help to understand how to correctly sign requests.
Let me know if you have any other questions,
Evan