interface OutboundPathProcessorInterface

PathProcessorLanguage.php in drupal/core/modules/language/lib/Drupal/language/HttpKernel/PathProcessorLanguage.php

Contains Drupal\language\HttpKernel\PathProcessorLanguage.

PathProcessorTest.php in drupal/core/modules/system/tests/modules/url_alter_test/lib/Drupal/url_alter_test/PathProcessorTest.php

Contains Drupal\url_alter_test\PathProcessorTest.

UrlGenerator.php in drupal/core/lib/Drupal/Core/Routing/UrlGenerator.php

Contains Drupal\Core\Routing\UrlGenerator.

interface OutboundPathProcessorInterface {

  /**
   * Processes the outbound path.
   *
   * @param string $path
   *   The path to process.
   *
   * @param array $options
   *   An array of options such as would be passed to the generator's
   *   generateFromPath() method.
   *
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The HttpRequest object representing the current request.
   *
   * @return
   *   The processed path.
   */
  public function processOutbound($path, &$options = array(), Request $request = NULL);

}