Description of the Wireless Client Update for Windows XP with Service Pack 2.

Microsoft Knowledge Base Article 917021 contains the following INTRODUCTION:

This article describes the Wireless Client Update for 32-bit versions of Microsoft Windows XP with Service Pack 2.

This update enhances support for Wi-Fi Protected Access 2 (WPA2) options in Wireless Group Policy. This update helps prevent a Windows wireless client from advertising the wireless networks in its preferred networks list.