Boardview for the Apple A1278 MacBook Pro 13-inch, packed in a ZIP archive of about 464 KB. The name gives no logic board number, and Apple produced several 820-series boards under the A1278 model number, so identify the correct one first. Read the 820 number printed on your logic board and compare it with the file once extracted. Boardview data, opened in tools like OpenBoardView or FlexBV, shows component positions, nets and test points for tracing shorts and missing power rails.
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.
Built-in OS tools7-Zip