Schematic for Apple logic board 820-2997, a PDF archived in an 841 KB RAR. The Mac model is not given in the name, so confirm the 820-xxxx number etched or printed on the logic board before using it. Apple diagrams like this let technicians trace power rails, follow enable signals through the power-up sequence and isolate shorted components. Open it in any PDF viewer, and check the board revision since components and values can change between versions of the same number.
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 @LaptopsBoardview. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.