ZIP package of about 242 KB for an H61M-C desktop motherboard. The name gives only the model, with no revision and no hint of the file type, so open the archive to see whether it holds a boardview, a BIOS image or other service data. Compare the model and revision printed on the board before relying on anything inside. At this size a boardview or a compact document is more likely than a full schematic. Any BIOS content should only be written to the SPI chip after backing up the original.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.