Boardview data for the N56DP mainboard at revision 2.2, compressed into a 210 KB RAR file. BDV identifies the content as layout information showing where every component sits and which nets connect them. It is useful for locating test points, tracing a shorted line to the offending part and finding components referenced in a schematic. Programs such as OpenBoardView, FlexBV or Boardviewer handle common boardview formats. Confirm that your board is marked 2.2, since other revisions can move or change parts.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.