RAR package for the Z87-DELUXE/DUAL, the Asus Intel Z87 Deluxe variant with dual onboard networking features, as indicated by the name; no revision or content type is given. At about 620 KB it likely carries a boardview or comparable repair layout. A technician uses such data to find components, test points and nets when diagnosing shorts or dead power rails. Do not mix it with the standard Z87-DELUXE file, and check the PCB revision before relying on component locations.
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.