api-8.x-1.x-dev/tests/modules/api_test/api_test.module

<?php

/**
 * @file
 * Test module for API module tests.
 */

/**
 * Implements hook_api_parse_functions_alter().
 */
function api_test_api_parse_functions_alter(array &$parse_functions) {
  // Parse '.foo' files as PHP.
  $parse_functions['foo'] = 'parsePhp';
}