Reference PDF for the 2SA1345 transistor, filed under schematics but most likely a component datasheet. Under the Japanese JIS naming system the 2SA prefix marks a PNP transistor intended for high-frequency use. A datasheet like this gives the pinout, package outline, absolute maximum ratings and electrical characteristics. Use it to confirm emitter, base and collector before testing in circuit with a multimeter diode range, and to judge whether a substitute part has adequate voltage, current and gain 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.