Made  in Output protected again, it was only ever made public by Eric to fix an issue with the Dwoo MY_Parser, which is no reason to change core files. That Parser doesn't really even need the acess.
diff --git a/system/core/Output.php b/system/core/Output.php
index bcba257..45a82f3 100644
--- a/system/core/Output.php
+++ b/system/core/Output.php
@@ -28,7 +28,6 @@
  */
 class CI_Output {
 
-	public $parse_exec_vars	= TRUE;	// whether or not to parse variables like {elapsed_time} and {memory_usage}
 	protected $final_output;
 	protected $cache_expiration	= 0;
 	protected $headers			= array();
@@ -36,6 +35,7 @@
 	protected $enable_profiler	= FALSE;
 	protected $_zlib_oc			= FALSE;
 	protected $_profiler_sections = array();
+	protected $parse_exec_vars	= TRUE;	// whether or not to parse variables like {elapsed_time} and {memory_usage}
 
 	function __construct()
 	{