Datasheet for the 2SA1289, presented as a 40.7 KB PDF and listed in the schematic category. Nothing beyond the part code is given by the name. In Japanese JIS numbering, 2SA marks a PNP transistor, so the document most likely covers pinout, packaging, maximum ratings and characteristic data. Technicians lean on such sheets when identifying legs on an unfamiliar package, confirming a gain grade, or checking that an equivalent device has comparable voltage, current and dissipation before installing 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 @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.