A boardview (component placement) file (board LA-N381P). Shared as “JDB41 LA-N381P r1.0 BOARDVIEW.zip” — a .zip file, 142 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 @cynetitsolution. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.