RAR archive of 1.05 MB for the ECS P965T-A motherboard, revision 1.0B. The letter suffix matters: check that your PCB is marked 1.0B and not plain 1.0, because minor revisions can change parts and layout. The name does not say what is inside, so expect a schematic or BIOS data and confirm after extraction. Schematics let you trace power rails, clocks and reset lines and track down a shorted component; any ROM image should be written with a programmer only after saving the original chip.
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.