Compressed RAR package, 402 KB, named for the H87-PRO desktop motherboard, a model built around the Intel H87 chipset. The name gives no revision or content type, so unpack it to see whether it holds a boardview, a schematic or both. Files of this size usually carry repair documentation that helps you find components, trace power rails such as VCCIN and standby voltages, and work out where a short sits. Compare the board revision printed near the slots with the one in the document before probing.
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.