ZIP package, 1.77 MB, for the MSI motherboard MS-6742. The file name gives no detail beyond brand and board code, so no revision, document type or firmware version can be assumed. Unpack it to find out what it includes. MS- codes are MSI's own model numbers, printed on the board, which lets you verify the match quickly together with the revision. Schematics open in a PDF reader for tracing circuits, while BIOS dumps go to a programmer only after the current chip has been read and saved.
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.