Apple logic board 820-3435 boardview, labelled J41 in the name, compressed into a 123 KB ZIP archive. Apple uses the 820-xxxx format for its logic board part numbers, and J41 appears to be an internal project code. A boardview lets the technician find components and test points and follow nets across the board while diagnosing power, charging or short faults. Extract the archive and open the layout in a viewer such as OpenBoardView or FlexBV. Make sure the 820 number silkscreened on the PCB matches before relying on the file.
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 @cynetitsolution. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.