The root config type for the URL Extractor to Header filter configuration file. Config type for a URL extraction to a header value. The name of the header to put the extracted value into. The regex to be applied to the URL in order to extract the desired value. The value will specifically be extracted from group 1 of the regex. For example, a regex of ".*/(hybrid:\d+)/entities/.+" and a URL of "/v1/hybrid:12345/entities/89" would result in the value of "hybrid:12345" being used as the header value. The default value to use when the regex doesn't match the URL. If no default attribute is supplied, the header will not be added in the event of no match.