RAR archive of 2.76 MB for Wistron board 12291-2, labelled spi 1, which suggests the first SPI flash dump from a two-chip setup. Board 12291-2 is a Wistron design used in the Lenovo ThinkPad W540 family. Identify which physical chip the dump belongs to before programming, and check that the image size equals the chip capacity. Read and save the original contents first, since the flash holds system-specific data, and confirm the board revision on the PCB.
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 @SCHEMATICWORLD. 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)