ZIP archive, 1.55 MB, named after the X751LKB model code, which follows ASUS laptop naming, although no brand is given in the listing. The name gives no board revision or contents, so open it to see whether it holds a schematic, boardview or BIOS. Material like this helps a technician follow power sequencing, find shorted capacitors and locate test points. Check the model and board revision on the motherboard label before applying any values or flashing images from the package.
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 @schematiclaptopramkushwaha. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.