Covering the 2SK1435, this 105 KB PDF is indexed as a schematic yet named after one discrete component, which suggests a datasheet. The 2SK prefix is the Japanese JIS code for an N-channel FET. Nothing else about the part, such as maker, case style or voltage class, can be read from the name. Typical uses are identifying the pinout when tracing a power stage, checking a shorted drain to source junction against expected behaviour, and selecting a substitute with comparable ratings.
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.