The 2SC5473 has its own 38.2 KB PDF, carrying an _E suffix that probably indicates the English-language version. It belongs to the JIS 2SC family of NPN transistors and, despite the schematic label, is most likely a component datasheet. It should give the terminal layout, case outline, absolute maximum ratings and characteristic data. Technicians use it when sourcing a substitute part or checking a suspected short. Confirm the package type and pin order before installing any replacement on the board.
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.