RAR archive of 189 KB for the H81M-R micro-ATX motherboard, an Intel H81 chipset board. The name is minimal and gives neither revision nor contents, so treat it as unidentified repair material until extracted. Most likely it holds a boardview or schematic, which is used to locate parts, trace power rails from the ATX connector to the CPU VRM, and find the component pulling a rail to ground. Before relying on it, compare the PCB revision with the one recorded in the document.
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 @boardview. 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.