RAR archive for the Lenovo IdeaPad Y510 tied to the Wistron B2M board design, as the name indicates. The 1.23 MB size fits a schematic or boardview package, though the exact contents are not listed. Wistron uses project code names rather than LA-style numbers, so compare the silkscreen on the PCB with the documents before trusting them. Technicians typically use such material to trace power rails, locate MOSFETs and test points, and follow the standby and main power sequence while diagnosing a no-power or no-boot fault.
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 @generalschematics. 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.