Weighing 332 KB, this PDF is titled 25C160, a name that resembles a serial memory part code, so treat it as a chip datasheet rather than a motherboard schematic. The name gives no further details on device, board or revision. When dumping or restoring such a chip, the document provides the pinout and voltage information needed to wire a programmer correctly. An image whose size differs from the chip capacity will not fit, so verify the marking on the package and back up its contents before any write.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.