An archive of repair files for MSI hardware (board MS-16K21). Shared as “MS-16K21_N17E-G1-A1.rar” — a .rar file, 80.5 KB.
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 @boardsscanrepo. 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.