RAR archive of 1.13 MB for the ECS 662T-M motherboard, revision 1.0. The file name provides only the board model and revision without describing the included files. Schematic material for such boards is typically used to follow the CPU core supply, memory voltage and chipset power and to check signals like power-good and reset during no-boot diagnosis. A revision 1.2 package for the 662T-M also exists, so confirm the revision silkscreened on your board before relying on this one.
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.