Service package for the MSI MS-7459 motherboard, revision 1.0, compressed in a 1.40 MB RAR archive. The name does not say whether it holds a schematic or boardview, so check the files after extraction. Material of this type is used to trace power rails from the ATX connector to the VRM, confirm enable and power-good signals, and find the right components when replacing failed MOSFETs or capacitors. MS-xxxx numbers are MSI's internal board codes; confirm the PCB carries the same number and revision 1.0.
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 @cyberlanelectonik. 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.