Apple logic board boardview for board 820-01700, a 204 KB RAR whose name also contains the tag LO25. Apple uses 820-xxxxx numbers for its logic boards, printed on the PCB itself. The name does not say which Mac model this board belongs to, so identify it from the board number. A boardview lets you search part references, highlight nets and find test pads for diagnosing shorts or missing rails, and it opens in viewers such as OpenBoardView or FlexBV after extraction.
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 @SCHEMATICWORLD. 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.