A 2.60 MB zip containing repair files for Apple board 820-2915 revision B. No device model is given, so rely on the board marking to confirm compatibility. The size suggests a schematic and probably a boardview are included. These are used to trace signals between components, verify rail voltages, read part values and pinpoint shorted capacitors or failed ICs. Open schematics in any PDF viewer and boardviews in OpenBoardView or FlexBV, after checking that the PCB number and revision letter match exactly.
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 @notebookschematic. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.