PDF reference for part 2SK1833, around 34.6 KB. Following JIS rules, 2SK identifies an N-channel FET, and the document is likely its datasheet despite the schematic label. It should list electrical characteristics, absolute limits and the mechanical outline. Technicians consult it to locate the gate, drain and source terminals, evaluate whether the device has failed and choose a replacement with equal or higher ratings. The name says nothing more, so confirm the marking on the component itself before trusting the match.
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.