See below for more info. RSS Get RSS feed with format=rss URL parameter. For example, http://shrub.appspot.com/s3hub?format=rss See limitations below. JSON Get list bucket response in JSON format with format=json URL parameter. For example, http://shrub.appspot.com/s3hub?format=json See limitations below. ID3 Lookup ID3 information (returned as JSON) for an MP3 with format=id3-json URL parameter.