Filed as a schematic, this 120 KB PDF is named only after the part number 2SC4402, so it is most likely the manufacturer datasheet for that transistor rather than a circuit drawing. Under the Japanese JIS scheme, the 2SC prefix marks an NPN bipolar transistor originally classed for high-frequency use. Technicians open such a sheet in any PDF reader to confirm the pinout, package outline, maximum ratings and marking code before replacing a suspect part. Always compare the body marking against the sheet before soldering in a substitute.
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.