A 365 KB PDF for the 2SK2859, filed under the schematic type though it is most probably a manufacturer datasheet. Nothing other than the part number appears in the name. The 2SK code follows JIS/JEITA registration and identifies an N-channel FET. During repair the sheet is consulted to find gate, drain and source, check maximum ratings against the circuit and compare on-resistance and capacitance with possible substitutes. Use any PDF viewer to open it and confirm the device marking before ordering a part.
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.