A boardview (component placement) file. Shared as “LSN-3 SWG MB H0226-2 T420S.bdv” — a .bdv file, 1.10 MB.
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 @ShareMan_Electronic_Files. Enginerys does not host this file.
How to open a .bdv file
Text-based boardview produced by Honhan / Hon Hai test tooling, with lightly obfuscated content.