An archive of repair files for Lenovo hardware (board NM-D521). Shared as “04 LCFC NM-D521 SCHBRD_xmxno1 ideapad3.rar” — a .rar file, 3.62 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 @boardviewsandachematics. 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)