Schematic for the board LA-L99GP, compressed in a 4.09 MB RAR archive; the LA- code is the Compal numbering scheme, though the name does not state the laptop brand or revision. Inside should be the circuit diagram, usually a PDF, covering power supply stages, CPU and memory rails, charging and peripheral interfaces. Technicians use it to trace signals, identify component values and find why a voltage rail fails. Match the board code and revision printed on the PCB before relying on it.
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 @bartonarquivos. 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.