e4f10a3c-49e6-405d-8288-a23bd4eeaa6c
System.FileExtension_3.X

e4f10a3c-49e6-405d-8288-a23bd4eeaa6c System.FileExtension_3.X

PKEY_FileExtension

//  Name:     System.FileExtension -- PKEY_FileExtension
//  Type:     String -- VT_LPWSTR  (For variants: VT_BSTR)
//  FormatID: E4F10A3C-49E6-405D-8288-A23BD4EEAA6C, 100
//  
//  This is the file extension of the file based item, including the leading period.  
//  
//  If System.FileName is VT_EMPTY, then this property should be too.  Otherwise, it should be derived
//  appropriately by the data source from System.FileName.  If System.FileName does not have a file 
//  extension, this value should be VT_EMPTY.
//  
//  To obtain the type of any item (including an item that is not a file), use System.ItemType.
//  
//  Example values:
//  
//      If the path is...                     The property value is...
//      -----------------                     ------------------------
//      "c:\foo\bar\hello.txt"                ".txt"
//      "\\server\share\mydir\goodnews.doc"   ".doc"
//      "\\server\share\numbers.xls"          ".xls"
//      "\\server\share\folder"               VT_EMPTY
//      "c:\foo\MyFolder"                     VT_EMPTY
//      [desktop]                             VT_EMPTY
0 Microsoft propkey.h
System.FileExtension_3.X

2.X PROPERTY : D5CDD505-2E9C-101B-9397-08002B2CF9AE/'FileExt'
3.X PROPERTY : E4F10A3C-49E6-405D-8288-A23BD4EEAA6C/100

from https://msdn.microsoft.com/fr-fr/library/windows/desktop/bb419046(v=vs.85).aspx
0 MS Property Mappings (from WDS 2.x to 3.x)
Include/10.0.16299.0/um/propkey.h:1591

//  FormatID: {E4F10A3C-49E6-405D-8288-A23BD4EEAA6C}, 100
in Include/10.0.16299.0/um/propkey.h:1591
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