Archive for Apple logic board 820-3437, with a leading 43 in the name that is not explained and may simply be a catalogue index. No model, revision or contents are stated, so unpack the 2.57 MB RAR to see whether it holds a schematic, a boardview or both. Apple uses the 820-xxxx numbering for its logic boards and prints the code on the PCB. With a matching board, the files help trace power rails, locate components and test points, and track down shorts.
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 @Mac_Shematic_Santale. 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.
7-ZipWinRARThe Unarchiver (macOS)