Listed as a schematic, this 183 KB PDF actually relates to the 2SC5259 part. JIS numbering places the 2SC prefix on NPN bipolar transistors, so the content is expected to be pinout, case drawing and electrical characteristics rather than a board circuit. It is handy when a stage has a shorted or open transistor and the replacement must be matched. Always compare the component marking with this part number, and choose an equivalent whose voltage, current and dissipation ratings are equal or higher.
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.