At 245 KB, this PDF for the 2SA1721 is one of the larger documents in the series, suggesting several pages of curves or package data. It is catalogued as a schematic, but the name is purely a part number; under JIS conventions 2SA identifies a PNP bipolar transistor, so treat it as the manufacturer datasheet. Consult it for pin assignment, maximum ratings and characteristic graphs when replacing a failed device, and match package and polarity exactly, since a wrongly oriented transistor can damage surrounding parts on power-up.
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.