Datasheet-style PDF for the 2SK669, a part number in the JIS 2SK series used for N-channel field-effect transistors, listed in the index as a schematic. The file is 61.6 KB, enough for characteristic curves along with the ratings tables. A repair technician would consult it to learn the package pinout, check drain-source voltage and current limits, and judge whether a substitute device is suitable. Measure the original part out of circuit before condemning it, and open the document in any ordinary PDF viewer.
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.