Archive of high-definition photos for the Apple A1278 MacBook Pro logic board 820-3115-A. At 1.67 MB it holds reference images of the board. Photos are useful for checking where missing or damaged components belong, verifying orientation of chips and connectors and comparing corrosion-damaged areas with an intact board. Pair them with a boardview or schematic for part values. The 820 number and revision letter on your logic board should match, since different A1278 boards have different layouts.
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 @pkbiosbdv. 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.