The 2SK2884 is the subject of this 428 KB PDF, indexed as a schematic though it is most likely the manufacturer datasheet for the part. Nothing beyond the number appears in the name. Under JEITA conventions 2SK stands for an N-channel field-effect transistor. Repair use centres on confirming the package outline and pinout, checking ratings against the circuit and finding an equivalent when the original is unavailable. Read the header of the PDF for the maker and confirm the body marking before fitting a replacement.
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.