The 2SK1613 transistor is covered by this 36.4 KB PDF. In Japanese JIS/JEITA numbering the 2SK prefix denotes N-channel FETs, making this a component datasheet rather than a circuit diagram. The file name lists no vendor or package. Technicians read such sheets to learn the lead arrangement, absolute maximum ratings and typical switching behaviour, which are needed to diagnose a suspected short and to choose an equivalent part when the exact number is hard to source.
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.