PDF schematic for the MSI MS-7782 motherboard; the file name gives no revision, chipset or date, so check those on the title block inside. MS-7xxx numbers are MSI's own desktop mainboard codes, printed on the PCB near the slots or edge. Such a diagram is used to trace power sequencing, locate the source of a shorted rail, identify unknown components by reference designator and follow signals to connectors. Any PDF viewer opens it, and searching net names speeds up work. Match the revision printed on your board before relying on values.
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 @pepeelectronica. 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.