Boardview for Apple logic board 820-02098, packed as a 189 KB ZIP. Apple identifies its logic boards with 820-xxxxx numbers printed on the PCB, and the model is not named here, so match that number on your board. A boardview shows part designators, nets and test points on both sides, which is essential for tracing rails like PP3V8 or locating a shorted capacitor. Depending on the inner format it opens in FlexBV, OpenBoardView or similar tools.
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 @cynetitsolution. 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