PDF schematic titled P552SJ, a 1.09 MB document; the RG suffix is not explained by the name, and no brand or board revision is given. The P552SJ designation matches a laptop model naming style, but the file itself should be opened to confirm the manufacturer and board number on its title block. A schematic like this is read in any PDF viewer and is used to trace power rails, locate the components on a failing circuit and check expected voltages. Make sure the board number printed on the PCB matches the one shown in the drawing before working from 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 @alischematics. 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.