Quanta AT8 laptop mainboard schematic, revision 1A, provided as a 1.37 MB PDF, apparently a duplicate copy given the (2) in the name. No brand, model or board number is stated. Technicians use schematics like this to trace the adapter, battery charger and system power rails, find the source of a short and check signal paths between chips. Quanta boards normally carry a DA0-prefixed number that includes the project code, so compare it and the revision before using this.
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 @abgm_manutencao_esquemas. 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.