Indexed as a schematic, the 54.3 KB PDF named 30LJQ045 is most likely a datasheet for a rectifier diode, the 045 grade within the LJQ series present in this collection. The name gives no laptop, board number or revision. Open it with any PDF reader to confirm electrical limits and package details when replacing a diode in a charging or regulator circuit. Because grades share a prefix, read the complete code on the component itself and ensure the replacement rating is equal or higher.
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 @cyberlanelectonik. 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.