ROOT CERTIFICATE |_____ISRG Root X1 |__________ISRG Root X2 |_______________E1 |____________________www.stackoverflow.comClick on a certificate to get more info.// PHP code to retrieve your certificate:// $g = stream_context_create (array("ssl" => array("capture_peer_cert" => true, "capture_peer_cert_chain" => true)));// $r = stream_socket_client("ssl://www.stackoverflow.com:443", $errno, $errstr, 30, STREAM_CLIENT_CONNECT, $g);// $cont = stream_context_get_params($r);// $certinfo = openssl_x509_parse($cont["options"]["ssl"]["peer_certificate"]);