Index: wp-includes/vars.php
===================================================================
--- wp-includes/vars.php	(revision 26811)
+++ wp-includes/vars.php	(working copy)
@@ -6,8 +6,11 @@
  * for the browser to set which one is currently being used.
  *
  * Detects which user environment WordPress is being used on.
- * Only attempts to check for Apache and IIS. Two web servers
- * with known permalink capability.
+ * Only attempts to check for Apache, Nginx and IIS -- three web
+ * servers with known pretty permalink capability.
+ *
+ * Note: Though Nginx is detected, WordPress does not currently
+ * generate rewrite rules for it. See http://codex.wordpress.org/Nginx
  *
  * @package WordPress
  */