File for the 2SC5321 in PDF form, 122 KB, listed among schematics yet named like a discrete-component datasheet. JIS numbering assigns 2SC to NPN bipolar transistors, so the pages most likely hold ratings tables, characteristic graphs and a package outline. Nothing in the name identifies the manufacturer or where the part was used. Match the code printed on the device first, then use the pinout to test junctions with a multimeter or to find a substitute with comparable voltage, current and gain.
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.