Only the part number 2SJ512 appears in the name of this 455 KB PDF, which the index lists among schematics. The JIS 2SJ prefix identifies P-channel FETs, so the file is most likely the transistor datasheet. Reading it in a PDF viewer gives absolute maximum ratings, threshold voltage, RDS(on), switching times and the package pin map, all needed when replacing a power switch or verifying a part with a diode test. Make sure suffix letters and case style on the original component agree with the sheet.
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.