ZIP archive named unpas3, about 3.8 MB, whose name gives no device, board number or file type. Without that information it is impossible to say whether it holds a firmware dump, a utility or documentation. Open and inspect the contents before use, check any binary with tools such as UEFITool, and compare its size with the target flash chip. If it proves to be a BIOS image, back up the original chip with a programmer before writing and confirm the board model matches.
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 @vinafix_bios. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip