Compressed package of 2.33 MB tied to Apple board 820-2838, with no model name or revision given in the file name. Apple marks its logic boards with 820-xxxx numbers, so the archive most likely holds a schematic, a boardview or both for that board. Open the contents with a PDF reader or a boardview tool such as OpenBoardView to trace rails, find test points and check for shorts. Compare the number and revision letter printed on the PCB with this one first, since revisions can differ in parts and layout.
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.