D8_rplf/modules/colorbox_inline/colorbox_inline.module

<?php

/**
 * @file
 * Enabled the "colorbox inline" functionality for Drupal 8.
 */

/**
 * Implements hook_page_attachments().
 */
function colorbox_inline_page_attachments(array &$page) {
  \Drupal::service('colorbox.attachment')->attach($page);
  $page['#attached']['library'][] = 'colorbox_inline/colorbox_inline';
}