Datasheet-style PDF of 105 pages' worth of nothing more than a part number: the 2SJ420, a device whose 2SJ prefix under Japanese JIS designation identifies a P-channel FET. At 102 KB it most likely holds the electrical characteristics, absolute maximum ratings and package drawing. No manufacturer or variant is stated in the name. Use it to verify gate, drain and source pins when testing the transistor in circuit, and compare voltage and current limits carefully before choosing an equivalent part for a repair.
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.