A schematic diagram for Apple hardware (board 820-2855). Shared as “A1370_A1370_820-2855-A.pdf.zip” — a .zip file, 1.37 MB.
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 @oficinacomputadores. 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