A 420 KB PDF covering the 2SJ402, whose 2SJ prefix under Japanese JIS designation marks a P-channel field-effect transistor. Filed as a schematic, it is really a datasheet with ratings, characteristics and outline. The name gives only the part number. A technician checks it for pinout, threshold voltage and current capability before replacement, and should verify the package on the board matches, since parts with close numbers may be offered in different cases with different pin orders.
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.