An archive of repair files for Lenovo hardware (board NM-A581). Shared as “bt462 nm-a581 rev 3.0_.rar” — a .rar file, 7.22 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 @anztechnology. 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)