For the 2SK1427 N-channel FET, this 101 KB PDF sits in the schematic section of the index but most likely contains a datasheet. The 2SK prefix comes from Japanese JIS semiconductor numbering. No other details, such as case outline or current rating, are stated in the name. A technician can use it to identify gate, drain and source, check voltage and current limits, and decide whether a proposed equivalent is suitable, after confirming the marking on the board component.
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.