845a8e7d_ption___MuOnline_Pentium_Tools__Why_to_edit_
[File Location] \Data\Local\ [File Name] ItemSetType.bmd [Description] Configuration of items that belong to ancient sets [Why to edit?] 
If you want to add\remove some items from ancient sets. The row number in that file matches to items row number in item.bmd. Set type number matches to ancitent set number in ItemSetOption file. You need that server side itemsettype.txt will be same(after editing you can export for server side file)
MuOnline Files Description - MuOnline Pentium Tools
Why to edit?