PDF schematic for a board identified as CG190PI, version 1.00, about 2.83 MB. The name does not give the laptop brand or model, so CG190PI is most likely the motherboard or project code printed on the PCB. A circuit diagram like this lets a technician follow power sequencing, check regulator feedback values and trace signals between the chipset, EC and connectors. Before using it, verify that the board marking reads CG190PI with the same revision, because component values can differ between versions.
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 @vinafix_bios. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.