RAR file for an Elitegroup desktop board named 865G M8, where ESC in the name is very likely a typo for ECS. The 865G reference points to the Intel 865G chipset as part of the model name. At about 997 KB the archive most likely contains schematic pages. Use them to trace VRM and memory power rails, find faults around the chipset and check component values. Extract with WinRAR or 7-Zip and match the model and revision printed on your mainboard before relying on any detail.
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.