Apple logic board archive for 820-3787 at revision A, a 520 KB ZIP. Apple identifies its logic boards with 820-xxxx numbers, and the letter suffix marks the board revision. The name does not specify contents or the Mac model, but compact Apple packages commonly hold boardview data, sometimes with a schematic. Check the 820 number etched on the logic board, then use the file to locate components, follow PP-named power rails and find test points while diagnosing power or short circuit faults in tools like OpenBoardView or FlexBV.
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 @ITHINKHS. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.