ECS (Elitegroup) archive tied to board number 558-1-4-01 with revision R21, roughly 905 KB in RAR format. The name does not state the contents, but packages of this size from ECS collections usually carry a schematic in PDF. The dashed numeric pattern resembles ECS internal PCB numbering, so match it against the label on the board. Extract with 7-Zip or WinRAR, then use the pages to trace supply rails, check for shorted capacitors and identify component locations. Make sure the R21 revision agrees with your PCB.
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.