This contains the file name extension of the file uploaded. It
is directly derived from the RawFilePath property. The file name
extension is typically a three character value (e.g. "txt") after
the terminating period of a file name - the RawFileType property
does not start with a period character.
Depending on the source Operating System and Browser this
property may contain characters such as question marks and slashes
which are illegal in file names on Windows. It may also contain