RAR package of 2.46 MB linked to MSI board number MS-7178. The name reveals nothing beyond the board, so the contents, possibly schematics or a BIOS image, have to be checked after unpacking with 7-Zip or WinRAR. MSI labels its desktop motherboards with MS-7 codes, visible on the PCB silkscreen. Verify the code and revision on the actual board, and treat any firmware inside carefully: back up the existing chip first and confirm the image size fits the installed flash part.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @IT_SERVICE_WORLD. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.