Datasheet candidate for the 2SC4455 transistor, a 100 KB PDF although filed with schematics. The 2SC prefix comes from Japanese JIS registration and designates NPN bipolar parts for high-frequency applications. No package type, maker or variant is named. In practice the sheet serves to look up lead identification, breakdown voltages, collector current and dissipation limits, which a technician needs when testing the part out of circuit or when hunting for a suitable equivalent with similar characteristics.
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.