You're using the PHP extension based on libtidy: https://github.com/gathercontent/htmldiff/blob/master/composer.json#L21 https://github.com/gathercontent/htmld

You're using the PHP extension based on libtidy: https://github.com/gathercontent/htmldiff/blob/master/composer.json#L21 https://github.com/gathercontent/htmldiff/blob/master/compos... http://php.net/manual/en/book.tidy.php http://php.net/manual/en/book.tidy.php