Dynamic Link Library files, like MSO.DLL, are essentially a 'guide book' that stores information and instructions for executable (EXE) files - like Setup.exe - to follow.
MSO.DLL is considered a type of Dynamic Link Library (DLL) file.
✻ Portions of file data provided by Exiftool (Phil Harvey) distributed under the Perl Artistic License. Windows® is a registered trademark of Microsoft Corporation. Microsoft® is a registered trademark of Microsoft Corporation.