mix-1.1.0-rc1/mix.install

<?php

/**
 * @file
 * Installation file of the Mix module.
 */

/**
 * Set default configuration for the Mix meta tags.
 */
function mix_update_8101(&$sandbox) {
  $config_factory = \Drupal::configFactory();
  $config = $config_factory->getEditable('mix.settings');
  $meta = [
    'frontpage' => [
      'active' => FALSE,
      'title' => '[site:name]',
      'description' => '',
      'keywords' => '',
      'metatags' => '',
    ],
    'node' => [
      'active' => FALSE,
      'description' => '[node:summary]',
    ],
  ];
  $config->set('meta', $meta);
  $config->save(TRUE);
}