Url.php

1. 8.x drupal/core/vendor/guzzle/http/Guzzle/Http/Url.php
2. 8.x drupal/core/vendor/symfony/validator/Symfony/Component/Validator/Constraints/Url.php
3. 8.x drupal/core/modules/views/lib/Drupal/views/Plugin/views/field/Url.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\Validator\Constraints;

use Symfony\Component\Validator\Constraint;

/**
 * @Annotation
 *
 * @author Bernhard Schussek <bschussek@gmail.com>
 *
 * @api
 */
class Url extends Constraint {
  public $message = 'This value is not a valid URL.';
  public $protocols = array(
    'http',
    'https',
  );

}