RAR archive of 2.24 MB labelled for the ASUS A8T.M, with no indication in the name of what the package contains, whether schematic, boardview or firmware. Open the archive and inspect the files before use, since the content type determines the tool you need: a PDF viewer for schematics, a boardview program for layouts or a flash programmer for dumps. Whatever is inside, confirm the model and board revision on the actual hardware match the documentation, and keep a backup of any original firmware before writing anything to a chip.
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.