- * @param int|string $key What the contents in the cache are called
- * @param string $group Where the cache contents are grouped
- * @param string $force Whether to force a refetch rather than relying on the local cache (default is false)
- * @return false|mixed False on failure to retrieve contents or the cache
- * contents on success
+ * @param int|string $key What the contents in the cache are called.
+ * @param string $group Optional. Where the cache contents are grouped. Default 'default'.
+ * @param string $force Optional. Unused. Whether to force a refetch rather than relying on the local
+ * cache. Default false.
+ * @param bool $found Optional. Whether the key was found in the cache. Disambiguates a return of
+ * false, a storable value. Passed by reference. Default null.
+ * @return false|mixed False on failure to retrieve contents or the cache contents on success.