Archive for the X45VD board, revision 3.0, about 163 KB in RAR format; the name does not say what it contains. Given its small size it is probably a boardview or a small document rather than a full BIOS image. Extract it with WinRAR or 7-Zip and identify the file type before use. A boardview lets a technician locate components, nets and test points; whatever the contents, the revision marked on the PCB should match 3.0 before relying on them.
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 @schematicslaptop. 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.
7-ZipWinRARThe Unarchiver (macOS)