Apple boardview for logic board 820-01987, revision 06, with no model name given in the file name. The .pcb layout shows components, nets and pin connections on both sides, letting a technician trace power rails, find test points and pinpoint which part shorts a line to ground. It opens with boardview programs such as OpenBoardView or FlexBV. Apple boards use the 820-xxxxx number with a revision suffix, so verify that -06 matches the marking on your PCB before relying on the layout for measurements.
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 @LaptopsBoardview. Enginerys does not host this file.
How to open a .pcb file
In repair archives a .pcb is typically an XZZ (XinZhiZao) boardview — popular for phones and recent laptops.