Glossary
Known folder GUID
A GUID identifying a shell namespace root or special folder, such as My Computer, Network, Recycle Bin or Downloads, in root shell items.
Root folder shell items (class type 0x1F) do not store a name: they store a GUID. 20D04FE0-3AEA-1069-A2D8-08002B30309D is My Computer (This PC), 645FF040-5081-101B-9F08-00AA002F954E the Recycle Bin, F02C1A0D-BE21-4350-88B0-7367FC96EF3C Network. Microsoft lists documented folder IDs under KNOWNFOLDERID.
A parser needs a lookup table to turn these into names; unknown ones are usually shown in braces. New Windows releases add roots such as Quick access or Home. See ShellBags on Windows XP, 7, 10 and 11.