Datasheet for the 2SC4605 in a 241 KB PDF, larger than most in this series and so likely to include more curves or package drawings. It is filed under schematics, yet the name holds only a JIS part number; 2SC indicates an NPN high-frequency transistor. Technicians read such documents for pinout, absolute maximum ratings and electrical characteristics before diagnosing a dead stage or swapping in an equivalent. Confirm the board marking matches this exact number 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.