A short 28.8 KB PDF for the 2SK2379, indexed as a schematic though it is almost certainly a component datasheet; JIS numbers starting with 2SK denote N-channel field-effect transistors. Nothing else is stated in the name. Readable in any PDF viewer, it should provide pinout and main electrical limits for confirming a replacement. Check that the marking on the actual part matches 2SK2379, and compare drain-source voltage and current before accepting a substitute.
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.