ASUS P7P55-M boardview, revision 1.01G, in a compact 106 KB RAR archive. The file describes the physical layout of this microATX board: where each resistor, capacitor, MOSFET and IC sits, and which nets connect them. A technician uses it alongside a multimeter to find test points, follow supply lines from the regulators and spot which components hang on a shorted rail. Formats like this open in OpenBoardView, FlexBV or Boardviewer. ASUS often changes layouts between revisions, so verify that 1.01G is printed on your board first.
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 @IT_SERVICE_WORLD. 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.