Overriding a config variable in Drupal 8

config_override.md

1. Find the form field in core. Usually I use the label or description field for this.
2. Check which configuration object and property is used for this field.
3. At sites/default/settings.php, uncomment the code that loads settings.local.php and create the file with the overrides. For example, here is how to set verbose logging:

$config['system.logging']['error_level'] = 'verbose';

4. Even though you may not see the form value change as in Drupal 7 (which is unfortunate), the configuration override will work.

I think it's better to use sites/default/settings.local.php and uncomment:

<?php

if (file_exists(__DIR__ . '/settings.local.php')) {
  include __DIR__ . '/settings.local.php';
}

Agree! I just updated with. Thanks.