Index: src/wp-includes/vars.php
===================================================================
--- src/wp-includes/vars.php	(revision 26907)
+++ src/wp-includes/vars.php	(working copy)
@@ -6,9 +6,13 @@
  * 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 permalink capability.
  *
+ * Note: The $is_nginx global serves only to differentiate between
+ * it and other web servers. No permalinks configuration rules are
+ * suggested for sites running the Nginx web server.
+ *
  * @package WordPress
  */