Small RAR archive of 1.18 MB named 2RS780MH-01. The code contains RS780, which matches the name of AMD's RS780 northbridge, but the name does not confirm the board maker, model or content type. MH-01 likely marks a board version. Extract it with 7-Zip or WinRAR to find out whether it is firmware or documentation. Before flashing, verify the identifier printed on the motherboard. Back up the original BIOS chip, and check that the image size matches the flash capacity.
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 @cyberlanelectonik. 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.