Listed as a schematic, this 90.1 KB PDF carries the code 84CNQ035, which matches the pattern of International Rectifier dual Schottky diode part numbers rather than any motherboard. It is most likely the datasheet for that rectifier. Repair use is straightforward: verify the common-cathode pinout, the case style and electrical limits when testing a suspected shorted diode in a power supply or replacing it. Make sure the full marking on the component, including any suffix, matches the title.
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.