Compressed ZIP package for the MSI MS-7518 board, about 1.05 MB. The name gives only the brand and board number, so it does not say whether the archive holds a schematic, boardview or BIOS image; extract it and check the contents. MS-7xxx numbers are MSI's own designations, mostly for desktop motherboards. Before using anything inside, compare the board number and revision silkscreened on the PCB with the files, and back up the original BIOS chip before writing any dump with a programmer.
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 .zip file
Compressed archive that every operating system opens without extra software.