RAR archive of about 395 KB named after the ASUS Q87M-A motherboard. The name gives no clue about the document type or board revision, so open it with 7-Zip or WinRAR to find out what is inside. Archives of this kind in repair collections typically hold boardview or schematic data, used for locating components, checking standby and main power rails, following signal paths around the Q87 chipset area and isolating shorts. Compare any revision noted inside with the one silkscreened on the board before trusting references.
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.