A 156 KB RAR archive labelled M4N78_SE, matching the ASUS M4N78 SE motherboard naming. The filename gives no indication of its contents, which could be a boardview, schematic or firmware, so inspect it after extraction. A boardview opens in tools like OpenBoardView for searching designators and highlighting nets during short hunting or rail tracing. If it contains a BIOS image, verify the size against the flash chip and save the original contents before programming with an external tool.
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 @boardview. 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.