Archive named only BoardViewer, so its exact contents cannot be confirmed from the name, though it is filed as boardview material of about 1.25 MB. It most likely holds a viewer utility or a boardview file rather than data for a specific board, and no model or board number is stated. Boardview software lets a technician locate components, follow nets between parts and find test points while measuring a live board. Unpack it and scan it for malware before running anything, then check which boardview formats it actually supports.
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 @Datalvela_servicios. 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.