prepopulate-8.x-2.3/tests/modules/prepopulate_test_unsafe/prepopulate_test_unsafe.module

<?php

/**
 * @file
 * Hooks for the prepopulate_test_unsafe module.
 */

/**
 * Implements hook_prepopulate_whitelist_alter().
 */
function prepopulate_test_unsafe_prepopulate_whitelist_alter(array &$whitelisted_types) {
  $whitelisted_types[] = 'checkbox';
  $whitelisted_types[] = 'checkboxes';
  $whitelisted_types[] = 'radio';
  $whitelisted_types[] = 'radios';
}