RAR archive of 3.07 MB for the MSI MS-7123 mainboard. Its contents are not described by the name, which gives no revision, BIOS version or file type. Archives like this commonly bundle a schematic for tracing signals and power rails or a BIOS dump for SPI reflashing. The MS-7123 code follows MSI's internal board numbering. Check the number and revision silkscreened on the PCB, and before writing firmware, back up the original and make sure the image size fits the chip.
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.