Archive named after the H87 Pro4, most likely the ASRock H87 Pro4 desktop board, although the brand is not written in the name. At 4.97 MB it probably contains a BIOS image, possibly compressed from a larger SPI dump. The usual use is restoring a board after a failed update by writing the flash chip with a CH341A-type programmer. Extract the archive first, check that the image size matches the chip capacity, and keep a backup of the original contents before writing anything.
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 @biositechyangiyer. 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.