This is an instance of class WP_Rewrite, which is used to enable Pretty Permalinks in Wordpress. It is set in the [wordpress root folder]/settings.php and the WP_Rewrite is defined in [wordpress root folder]/wp-includes/classes.php.
The linked codex document has all the details about the class and the global variable’s usage. In a nutshell, the plugin authors can use this global variable to extend and customize rewrite rules and permalinks.
Back to full list of global variables.
Technorati tag: wp_rewrite, permalinks

April 27th, 2006 at 3:31 pm
[...] $wp_rewrite [...]
October 23rd, 2007 at 8:16 pm
[...] $wp_rewrite [...]