2SC4548 is the sole identifier on this 109 KB PDF, which the index lists as a schematic though it most likely contains a transistor datasheet. The 2SC prefix, per the Japanese JIS system, designates an NPN bipolar transistor for high-frequency use. No vendor or package is named. Use it for pinout and outline drawings, absolute maximum ratings and characteristic curves when testing or substituting the part, and verify the marking on the physical component first.
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.