Named after the JIS designation 2SK184, this 307 KB PDF is tagged as a schematic but is most likely the device datasheet. The 2SK prefix identifies an N-channel field-effect transistor. Technicians consult such sheets to locate gate, drain and source on the package, read breakdown voltage and current figures, and confirm whether a proposed equivalent is suitable. Some JIS FETs are sold in graded ranks marked by a letter, so note any suffix on the original component before buying 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.