Here the 2SK1730 is documented in a 97.1 KB PDF. The 2SK prefix belongs to the Japanese JIS/JEITA register and indicates an N-channel field-effect transistor, so the content is a part datasheet despite the schematic category. No vendor, version or package appears in the name. Use the ratings tables and outline drawing to confirm the footprint and pinout, and cross-check any substitute against breakdown voltage, continuous drain current and switching characteristics before soldering it in.
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.