PDF of 116 KB named after the 2SC4865, listed among schematics though the name signals a discrete part. According to JIS/JEITA numbering, 2SC denotes an NPN bipolar transistor, so treat this as its datasheet. Usual contents are absolute maximum ratings, electrical characteristics and a mechanical drawing. A repair technician uses it to verify terminal order before multimeter diode checks, to confirm the part suits the circuit voltages, and to cross-reference a substitute with a compatible footprint.
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.