Boardview file for a board identified only as GC2. The name marks it as boardview in BRD format, packed in a small 136 KB RAR archive. No brand or device is stated, so check that the board code printed on the PCB matches before relying on it. BRD files open in viewers such as OpenBoardView, FlexBV or Boardviewer. They show part placement, net names and pin connections, which helps you find test points, follow a signal between components and measure for shorts. Pair it with the matching schematic for full circuit context.
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.