Validates a URL for use in a redirect.
Checks whether the $location is using an allowed host, if it has an absolute path. Therefore, a plugin can set or remove allowed host(s) to or from the list. If the host is not allowed, then the redirect is to $default supplied @uses apply_filters() Calls 'allowed_redirect_hosts' on an array containing WordPress host string and $location host string.
wp_validate_redirect() is located in