Part datasheet for the 2SC4484, a 134 KB PDF. Japanese JIS numbering uses 2SC for NPN bipolar transistors, which identifies the device class here; nothing else is given by the file name. Expect electrical characteristics, maximum ratings and dimensions. It helps when checking a transistor that measures shorted, and when looking for an equivalent with compatible voltage, current and dissipation figures. Double check lead order against the drawing, since substitutes sometimes swap pins.
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.