RAR archive for the MSI MS-7407 board, 4.56 MB in size. The name gives only the board number, with no revision or contents listed, so open it to see whether it holds a schematic, a boardview or a BIOS image. MS-7xxx numbers are MSI's own scheme for desktop motherboards, used on retail boards and on boards built for OEM partners. Before tracing power rails or flashing anything, confirm that the board number and revision printed on the PCB match the documents inside.
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.