Archive tied to Wistron board number 18448-1, about 16.7 MB in RAR format; the name gives no brand, revision or file type. Wistron uses five-digit project numbers with a suffix for its laptop motherboards, and the same number appears on the PCB. The contents may be a schematic, boardview or firmware, so check inside before use. With schematics, trace power rails and signals to locate faults; with firmware, back up the original SPI chip and match image size with the flash capacity.
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 @biositechyangiyer. 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.