We usually build non-English-language Drupal sites for our clients. The site usually ends up to have German as the default language for the production site. In local environments, we set the site to use English as the default language.
Now in Drupal 8, we are looking to do the same thing. I have a settings.local.php with which I try to override some config variables. I succeed with things like site name or preprocess css and preprocess js. I do not succeed with default_langcode.
Language module is enabled and default language in the UI is set to German.
Here is the code I use to try and override it to English:
$config['system.site']['default_langcode'] = 'en';
Is the default language even supposed to be overridden?