You would need to use the Microsoft Update Catalog (historical archive) or look for archived KB articles via the Internet Archive's Wayback Machine , as Microsoft has retired most pre-IE9 documentation from its live websites.
Released in the summer of 2000, IE5 SP2 wasn't a revolution. It was a refinement. It was the browser that bridged the gap between the chaotic innovation of the late 90s and the "design by committee" era of the mid-2000s. If you were browsing the web on a Windows 98 Second Edition or a fresh Windows 2000 machine, this is likely the specific version that carried you into the new millennium. microsoft internet explorer 5.0sp2