Schematic in PDF for the Apple MacBook Pro model A1708, logic board 820-00840, revision A. Apple 820-prefixed numbers identify the logic board design, and the suffix letter marks the revision printed on the PCB. A technician uses the diagram to follow power sequencing, check rail names and signal paths, and understand which component powers each section. Any PDF reader can open it, and it is often used alongside a matching boardview to locate parts physically. Confirm the board number on the logic board before applying 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 @hrtechno. 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.