Apple firmware archive for the logic board numbered 820-3332, revision A as given in the name. The zip, about 4.87 MB, most likely holds a boot ROM dump for the MacBook SPI flash, though the exact model is not named. Apple uses the 820-xxxx pattern for its own logic board part numbers, so match the number and revision silkscreened on the PCB before flashing. Read and save the original chip contents with a programmer first, and confirm the image size equals the capacity of the flash chip on the board.
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 @bios_laptop. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →