A boardview (component placement) file for Apple hardware (board 820-01700). Shared as “A2141 820-01700 X970 SCHEMATIC BORD.rar” — a .rar file, 8.51 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 @Laptopbiossolutions. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.