A boardview (component placement) file (board 18835-1). Shared as “18835-SC 18835-SD 18835-1 BOARDVIEW.rar” — a .rar file, 148 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 @pkbiosbdv. 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)