https://learn.microsoft.com/en-us/uwp/api/windows.storage.storagefile.folderrelativeid?view=winrt-26100
StorageFile.FolderRelativeId Property (Windows.Storage) - Windows apps | Microsoft Learn
Gets an identifier for the file. This ID is unique for the query result or StorageFolder that contains the file and can be used to distinguish between items...
propertywindowsstorageappsmicrosoft