apply_filters( 'comment_notification_headers', string $message_headers, string $comment_id )

1757		 *1758		 * @since 1.5.21759		 *1760		 * @param string $message_headers Headers for the comment notification email.1761		 * @param string $comment_id      Comment ID as a numeric string.1762		 */1763		$message_headers = apply_filters( 'comment_notification_headers', $message_headers, $comment->comment_ID );1764 1765		foreach ( $emails as $email ) {1766			$user = get_user_by( 'email', $email );1767 1768			if ( $user ) {1769				$switched_locale = switch_to_user_locale( $user->ID );