Part 2SK1890, documented in a 96.7 KB PDF placed in the schematic category. Japanese JIS numbering reserves 2SK for N-channel FETs, so this is a component datasheet rather than a board diagram. It supports testing and replacement work by giving the pinout, absolute maximum ratings and package outline, which you need to judge whether a substitute will survive in the same circuit. The name lacks maker and package information, so compare the part's printed code before relying on it.
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.