Strange variables in file module

These came up when reviewing #1804394: convert file.module variables to CMI. I can't understand why they're there.

     $element['description'] = array(
-      '#type' => variable_get('file_description_type', 'textfield'),
+      '#type' => $config->get('description.type'),
       '#title' => t('Description'),
       '#value' => isset($item['description']) ? $item['description'] : '',
-      '#maxlength' => variable_get('file_description_length', 128),
+      '#maxlength' => $config->get('description.length'),