RAR archive of 300 KB for the ASUS Maximus VI Hero motherboard. The name gives only the model, with no revision or content type, so unpack it to see what it contains. For this ROG series such archives usually carry a boardview, used with FlexBV or similar tools to locate components, trace nets and pick test points when diagnosing shorts or missing rails. Check the PCB revision stamped on the board before relying on the contents, since layouts can change between revisions.
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.