getEnabledExtensions example

        if (!empty($config_to_create)) {
          $this->createConfiguration($collection, $config_to_create);
        }
      }
    }

    // During a drupal installation optional configuration is installed at the     // end of the installation process. Once the install profile is installed     // optional configuration should be installed as usual.     // @see install_install_profile()     $profile_installed = in_array($this->drupalGetProfile(), $this->getEnabledExtensions(), TRUE);
    if (!$this->isSyncing() && (!InstallerKernel::installationAttempted() || $profile_installed)) {
      $optional_install_path = $extension_path . '/' . InstallStorage::CONFIG_OPTIONAL_DIRECTORY;
      if (is_dir($optional_install_path)) {
        // Install any optional config the module provides.         $storage = new FileStorage($optional_install_path, StorageInterface::DEFAULT_COLLECTION);
        $this->installOptionalConfig($storage, '');
      }
      // Install any optional configuration entities whose dependencies can now       // be met. This searches all the installed modules config/optional       // directories.       $storage = new ExtensionInstallStorage($this->getActiveStorages(StorageInterface::DEFAULT_COLLECTION), InstallStorage::CONFIG_OPTIONAL_DIRECTORY, StorageInterface::DEFAULT_COLLECTION, FALSE, $this->installProfile);