Small 20.5 KB PDF named for 2N5551 with a UTC tag, which most likely refers to the manufacturer that published this version. Filed as a schematic, it is in practice expected to be a component datasheet. No board number, laptop model or revision is given. The sheet helps confirm pin order, package and maximum ratings, and comparing makers is useful because second-source parts can differ in details. Check the marking and package on the actual part before using it as a reference for replacement.
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.