Hosts the Windows XP SP4 Unofficial installer as a standalone update package for existing installations. The Windows XP Unofficial Service Pack 4! - Overview & Demo
Typically bundles Internet Explorer 8, Windows Media Player 11, and .NET Framework versions 1.0 through 4.0.
Includes all official updates and hotfixes released by Microsoft for Windows XP until the end of its life.
Often integrates the BitLocker To Go Reader and XPS Viewer EP. Where to Find It
You can find various versions and ISO images of the Unofficial SP4 on community preservation sites: