PDF schematic named S22 MB VB, about 1.14 MB. The name suggests a main board drawing, but the brand, model and board maker are not stated, and VB is not expanded here because its meaning is uncertain. Check the title block inside the document and the PCB markings to confirm it is the right design. Schematics like this are used to trace supply rails, follow enable and power-good signals, locate test points and narrow down a short. Confirm revisions match before working from 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 @ithinkhs_casediscussion. 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.