using output=json does not show warnings


I am checking pages using the following curl command:

curl -sF 'uploaded_file=@test.html;type=text/html' -F output=json

This is the output I get:

     "url": "test.html",
     "messages": [

               "lastLine": 12,
               "lastColumn": 26,
               "message": "end tag for element \"em\" which is not  
               "messageid": "79",
               "explanation": "    <p class=\"helpwanted\">\n      <a 
\n        href=\"feedback.html?uri=;errmsg_id=79#errormsg\"\n\ttitle= 
\"Suggest improvements on this error message through our feedback  
channels\" \n      >&#x2709;</a>\n    </p>\n\n    <div class=\"ve  
mid-79\">\n    <p>\n      The Validator found an end tag for the  
above element, but that element is\n      not currently open. This is  
often caused by a leftover end tag from an\n      element that was  
removed during editing, or by an implicitly closed\n      element (if  
you have an error related to an element being used where it\n      is  
not allowed, this is almost certainly the case). In the latter case 
\n      this error will disappear as soon as you fix the original  
problem.\n    </p>\n    <p>\n      If this error occurred in a script  
section of your document, you should probably\n      read this <a  
href=\"docs/help.html#faq-javascript\">FAQ entry</a>.\n    </p>\n  </ 
               "type": "error"

     "source": {
         "encoding": "utf-8",
         "type": "text/html"

The json output shows errors, but it does not appear to show  
warnings.  I would expect to see the warning message, and a message  
type : info.

Is there something else I need to do in order for this to show up?

The page used for testing has been uploaded to here:

Received on Tuesday, 8 November 2011 12:23:54 UTC