Service archive for the Apple A1278 MacBook Pro 13-inch, J30 platform, built on logic board 820-3115 revision B, packed as a 2.39 MB ZIP. A package of this size most likely contains the schematic and possibly boardview data for that board. Apple identifies logic boards by the 820-xxxx number silkscreened on the PCB, so confirm the number and revision letter before relying on the files. The documents help trace power rails such as PPBUS, check the SMC power sequence and locate components while hunting a short.
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 @ITHINKHS. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.