PDF datasheet, 173 KB, covering the 2SK1740. The 2SK series in JIS nomenclature consists of N-channel FETs, and this document is likely its specification sheet. It typically lists breakdown voltage, drain current, on-resistance, capacitance and the package drawing. Technicians open it in a PDF reader to identify pins before measurements and to pick a replacement with equal or better ratings. The file name states only the part number, so check the marking and footprint on the PCB before using it.
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.