`Link` post format doesn't actually show external link

I havent’t looked too closely, but is $meta['_link_url'][0] the correct links to display as external link?

I was using the default Link post format with Twenty Thirteen theme, and they appear to check for links with this custom function

/**
 * Return the post URL.
 *
 * @uses get_url_in_content() to get the URL in the post meta (if it exists) or
 * the first link found in the post content.
 *
 * Falls back to the post permalink if no URL is found in the post.
 *
 * @since Twenty Thirteen 1.0
 *
 * @return string The Link format URL.
 */
function twentythirteen_get_link_url() {
	$content = get_the_content();
	$has_url = get_url_in_content( $content );

	return ( $has_url ) ? $has_url : apply_filters( 'the_permalink', get_permalink() );
}