chromium/src/third_party/blink/web_tests/http/tests/xmlhttprequest/resources/echo-auth.php

<?php
  if (!isset($_SERVER['PHP_AUTH_USER'])) {
   echo 'No authentication';
  } else {
   echo "User: {$_SERVER['PHP_AUTH_USER']}, password: {$_SERVER['PHP_AUTH_PW']}.";
  }
?>