RAR archive for the Z87-EXPERT, a high-end Intel Z87 workstation-class motherboard name from Asus, with no revision or content details in the name. The modest 370 KB size points to a boardview or similar repair document rather than BIOS. Such files let a technician find component positions, VRM phases and test points and follow nets when diagnosing a no-power or short condition. Open it to confirm format, and compare the revision printed near the PCB edge with the one in the file.
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.