ZIP package of roughly 863 KB labelled CAD Boardview, most likely a viewer utility for .cad boardview files rather than the layout of any specific motherboard, since the name lists no model or board number. CAD-format boardviews are common for Wistron-designed laptop boards, and a matching viewer lets a technician find components, follow nets and locate test points. Unpack it with any archive tool, check its contents and scan executables before running them on a bench computer.
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 @ITHINKHS. 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