rem: aFeed.downloadCallback.downloaded(aFeed, kNewsBlogInvalidFeed); 
add: aFeed.downloadCallback.downloaded(aFeed, aFeed.request.status == 304 ? kNewsBlogNoNewItems : kNewsBlogInvalidFeed); 
context:   onParseError: function(aFeed)   {    if (aFeed && aFeed.downloadCallback)    {      if (aFeed.downloadCallback)        aFeed.downloadCallback.downloaded(aFeed, kNewsBlogInvalidFeed);      FeedCache.removeFeed(aFeed.url);    }  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/9bcb6ac5890d02cdf768addc43a1136c68e49f48/Feed.js/buggy/mail/extensions/newsblog/content/Feed.js