A 168 KB PDF filed as a schematic and titled for the 8AF series. No device, brand or board number is named, so it most likely documents a component family rather than a whole motherboard. Technicians usually open a document like this to read pin assignments, package markings and typical application circuits when identifying or replacing a part. Check that the code printed on the chip on your board matches this series and its package before relying on any pinout or voltage figures.
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.