RAR archive for the ASUS A55BM motherboard, variant marked E in the name, about 293 KB in size. The name does not say what is inside, so it could hold a BIOS image, a boardview or a schematic set; open it and check the file extensions before use. ASUS desktop boards of this class usually store firmware on a socketed or soldered SPI chip that can be rewritten with a programmer such as a CH341A. Confirm the exact model and revision printed on the PCB, and save a backup of the original chip contents before writing anything to it.
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.