Manufacturer documentation for the 2SK1066 transistor, a 303 KB PDF. Under JIS numbering, 2SK parts are N-channel field-effect transistors, so despite the schematic label this is most likely a full datasheet with characteristic curves and package drawings. It helps when diagnosing shorted MOSFETs, verifying pin orientation and comparing specifications of possible substitutes. Open it in any PDF viewer. Ensure the marking on the installed device really reads K1066, since the 2S prefix is usually omitted on the package.
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.