Boardview for the Apple A1181 MacBook logic board 820-2279, revision A, packed in a small ZIP archive; BDV in the name marks the boardview type. The file maps component placement and net connections, so a technician can click a part, see what it connects to and find nearby test points. Viewers such as OpenBoardView or FlexBV open most boardview formats. Use it alongside the 820-2279 schematic and confirm the board number on the PCB before probing, since A1181 units shipped with various logic boards.
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 @schematics_boardview. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.