Compressed RAR archive of 583 KB for the Lenovo U350 notebook. The file name gives only the model, with no board number, revision or document type, so the contents are known only after extraction. Archives like this in repair collections usually carry a schematic or boardview used to trace power rails, find test points and locate components around a short. Before relying on it, compare the board code silkscreened on your PCB with the one inside the documents.
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 @schematicslaptop. 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)