Archive for the Lenovo Z580 with the code LZ3A, a 1.57 MB RAR whose exact contents are not stated. LZ3A corresponds to a Quanta platform code, and the archive probably holds a schematic for tracing power rails, checking shorts and finding component values. Open it with WinRAR or 7-Zip to see what is inside. Before relying on it, compare the board number and revision printed on the PCB with the documentation, since Z580 units were made with more than one board.
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 @hrtechno. 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)