Compressed archive called H81M2, about 224 KB, with no manufacturer, revision or content description in the name. The H81 part suggests an Intel H81 chipset desktop board, but which vendor's model is not stated, so confirm the exact board before use. At this size the RAR more likely holds boardview or schematic data than a BIOS dump. Extract it, identify the file type and open it in the matching viewer, then verify the model and revision printed on the PCB match before trusting it for diagnosis.
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.