This 100 KB PDF, catalogued as a schematic, bears only the designation 2SJ268. Under the JIS convention, 2SJ marks a P-channel FET, so the file most probably holds the manufacturer datasheet for that transistor. Expect pinout, absolute maximum ratings, characteristic curves and package dimensions, all useful for in-circuit testing or selecting a substitute during repair. Opening it requires nothing more than a standard PDF reader. Confirm the marking on the original component and the lead order before soldering in any alternative.
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.