For the transistor 2SA2039 this 40.2 KB PDF most likely provides the manufacturer datasheet, even though it sits in the schematic category. JIS numbering assigns the 2SA prefix to PNP bipolar transistors. Other details such as package, maker or gain class are not in the name. Use the electrical tables to verify a suspect part, check base-emitter and collector junctions with a meter using the pinout, and confirm that a substitute shares the same polarity, footprint and ratings.
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.