What is the deal with config collections?
Collections are for configuration overrides. Mainly used for translations, but could be used for other purposes as well. You can list the available collections in your Drupal installation, starting with the default collection (empty string):

$collections = \Drupal::service('config.manager')-&gt;getConfigCollectionInfo()-&gt;getCollectionNames();


More info https://www.drupal.org/node/2268523