diff -u b/sites/default/default.settings.php b/sites/default/default.settings.php
--- b/sites/default/default.settings.php
+++ b/sites/default/default.settings.php
@@ -224,16 +224,16 @@
  *
  * The $config_directories array specifies the location of file system
  * directories used for configuration data. On install, the "sync" directory is
- * created. This is used for configuration imports. The active directory is not
- * created by default, since the default storage for active configuration is
- * the database rather than the file system (This can be changed. See "Active
+ * created. This is used for configuration imports. The "active" directory is
+ * not created by default since the default storage for active configuration is
+ * the database rather than the file system. (This can be changed. See "Active
  * configuration settings" below).
  *
- * The default location for the sync directory is inside a randomly-named
- * directory in the public files path. This setting allows you to override
- * this location. If you use files for the active configuration, you can
- * enhance security by putting the active configuration outside your
- * document root.
+ * The default location for the "sync" and "active" directories is inside a
+ * randomly-named directory in the public files path. The below setting allows
+ * you to override the "sync" location. If you use files for the "active"
+ * configuration, you can enhance security by putting the active configuration
+ * outside your document root with CONFIG_ACTIVE_DIRECTORY.
  *
  * Example:
  * @code
@@ -580,8 +580,10 @@
  * By default, the active configuration is stored in the database in the
  * {config} table. To use a different storage mechanism for the active
  * configuration, do the following prior to installing:
- * - Create a folder for the active directory and define the path in
- *   $config_directories with the array key 'active'.
+ * - Create an "active" directory and declare its path in $config_directories
+ *   with the array key 'active' for the Configuration system to know about it.
+ *   Explanation about the $config_directories array is available above in this
+ *   file under the 'Location of the site configuration files' section.
  * - Override the 'bootstrap_config_storage' setting here. It must be set to a
  *   callable that returns an object that implements
  *   \Drupal\Core\Config\StorageInterface.