related to #1693 changed smarty version to 4.1.0

include/smarty/docs/programmers/api-variables/variable-debugging-ctrl.md

@@ -0,0 +1,20 @@
+\$debugging\_ctrl {#variable.debugging.ctrl}
+=================
+
+This allows alternate ways to enable debugging. `NONE` means no
+alternate methods are allowed. `URL` means when the keyword
+`SMARTY_DEBUG` is found in the `QUERY_STRING`, debugging is enabled for
+that invocation of the script. If [`$debugging`](#variable.debugging) is
+TRUE, this value is ignored.
+
+
+    <?php
+    // shows debug console only on localhost ie
+    // http://localhost/script.php?foo=bar&SMARTY_DEBUG
+    $smarty->debugging = false; // the default
+    $smarty->debugging_ctrl = ($_SERVER['SERVER_NAME'] == 'localhost') ? 'URL' : 'NONE';
+    ?>
+
+See also [debugging console](#chapter.debugging.console) section,
+[`$debugging`](#variable.debugging) and
+[`$smarty_debug_id`](#variable.smarty.debug.id).