Small 23.4 KB PDF for the 2SK2660 transistor. The 2SK designation comes from the Japanese JIS system for N-channel FETs, so the file is most likely a brief datasheet listing key ratings, the pinout and the package type. A technician would use it to identify drain, gate and source when testing the part. It also gives the essential limits for picking a replacement. Because short sheets sometimes omit curves, look for a fuller edition if switching characteristics matter.
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.