RAR archive for the MSI MS-6507 motherboard, revision 5.0, 386 KB. The name gives brand, board number and revision but not the document type, so extract it to see whether it is a schematic or BIOS. Several MS-6507 revisions exist in this collection, including 0A, 0B and 1.0, so matching the revision printed on the PCB is essential. Layout and parts may change between them. If firmware is inside, back up the original chip before writing a new image.
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.
7-ZipWinRARThe Unarchiver (macOS)