Schematic labelled Z65, stored as a PDF of about 1.6 MB. The name carries only this short code, with no brand, model or revision, so the title block inside is needed to identify the exact board and its version. Before relying on the drawing, compare the code and revision on the PCB. A technician uses circuit diagrams like this to follow power sequencing from adapter input to CPU supplies, check enable and reset signals, and find the components to test on a board that will not start.
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 @alischematics. 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.