Schematic document named Z65, about 1.57 MB in PDF format, with no brand, board number or revision stated beyond that short code. The title block should show the manufacturer and revision, which must be checked against the board. A diagram like this is used to trace power rails, read the power-up sequence, locate test points and identify components on a shorted rail. Any PDF reader opens it. Confirm that the PCB marking matches before relying on reference designators or 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 @schematicslaptop. 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.