An archive of repair files for Lenovo hardware (board NM-A841). Shared as “CG521 NM-A841 (REV 1.0).zip” — a .zip file, 2.67 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 .zip file
Compressed archive that every operating system opens without extra software.