Datasheet-style PDF of 107 KB for the 2SK3019, placed in the schematic section of the catalogue. In the JEITA scheme, 2SK identifies N-channel field-effect transistors. A technician turns to such a file to confirm gate, drain and source positions, read voltage and current limits, and find a suitable equivalent when the original part is damaged. The name states only the part number, so the maker, package and exact ratings should be read from the document and checked against the board.
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.