/**
 * Implements hook_file_download().
 */
function {{ machine_name }}_file_download($uri) {
  // Check to see if this is a config download.
  $scheme = StreamWrapperManager::getScheme($uri);
  $target = StreamWrapperManager::getTarget($uri);
  if ($scheme == 'temporary' && $target == 'config.tar.gz') {
    return [
      'Content-disposition' => 'attachment; filename="config.tar.gz"',
    ];
  }
}