RAR archive for an Apple Mac with board code J113 and logic board number 820-00165, revision A. Contents are not listed, so check whether it holds a schematic, boardview or both after unpacking. Apple 820-series numbers and their revision letter are printed on the logic board and should match exactly, since revisions can differ in components. Such material is used to trace power rails, locate test points and identify parts on a shorted line. Schematics open in a PDF reader, boardviews in OpenBoardView or FlexBV.
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 @alischematics. 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.