note 8260 added to Preface

http://www.php.net/manual/html/features.http-auth.html says that Lynx does not clear the authentication credentials with a 401 server response, so pressing back and then forward again will open the resource (as long as the credential requirements haven't changed). You could mention that it's possible for Lynx to 'forget' authentication if the user presses '_' http://www.php.net/manual/preface.php