A 40.8 KB PDF on the 2SK2012, an N-channel FET according to the JIS 2SK naming convention. Although classified as a schematic, it should contain the part datasheet: package drawing, pin configuration and electrical ratings. Technicians refer to it when a transistor in a switching or power stage is suspected of shorting, to measure the correct pins and choose a replacement with sufficient ratings. Only the bare part number appears in the name, so match suffixes and package on the original device.
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.