Lowercase-named PDF for the 2sc4997, 51.2 KB, indexed as a schematic. Only the part number is given. Japanese JIS/JEITA transistor numbering reserves the 2SC prefix for NPN bipolar types, so this should be a single-part datasheet covering ratings, pinout and outline dimensions. During board repair it helps identify a component by its marking, confirm which pin is which before out-of-circuit testing, and verify that a candidate substitute offers equal voltage and current capability in a compatible package.
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.