A boardview (component placement) file (board DA0G3EMBCD0). Shared as “DA0G3EMBCD0 G3EA.brd.zip” — a .zip file, 139 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 @dtechbios. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.
Built-in OS tools7-Zip