I can't explain it's location but the "What is it" part is here, This is a copy and paste from the "Help and Support" section of XP. If you type quick launch into the search section of the XP "Help and Support" section, you will get a lot of information about it.
A customizable toolbar that lets you display the Windows desktop or start a program (for example, Internet Explorer) with a single click. You can add buttons to start your favorite programs from the Quick Launch location on the taskbar.
OK. I know. It took me some time to find it at Documents and Settings\User\Application Data\Microsoft\Internet Explorer\Quick Launch. ("Search" did not help, even with view all files).
Why is it "in" Internet Explorer ? I would have thought the appropriate place would be at the "Windows" folder, or if it need to be at Application Data, then so be it, but under IE ?
Comments and explainations welcome. Thanks.