ZIP package of about 130 KB for the Apple A1502 MacBook Pro 13-inch, logic board 820-3476 revision A. The small size points to a boardview or a firmware dump rather than a full schematic, though the name does not say which. Apple identifies boards by the 820 number on the PCB, so confirm it and the revision letter first. Boardview data helps locate components and trace nets while hunting a short. A BIOS image requires backing up the original SPI flash with a programmer before writing.
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.
Built-in OS tools7-Zip