RAR package for the Elitegroup RS780M-A2 motherboard, revision VA, around 1.19 MB. The RS780 in the model name points to the AMD RS780 chipset family, while VA is the revision marking to look for on the PCB. Contents are most likely the schematic, which lets a technician trace CPU and memory power, locate SuperIO and BIOS circuitry and check for shorted components. Extract with 7-Zip or WinRAR and confirm model and revision against the board before trusting values.
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.