A compact 27.8 KB PDF named after 2SJ164, a JIS designation identifying a P-channel FET. The small size suggests a short datasheet, perhaps only a page or two with ratings and pinout, despite being catalogued as a schematic. When replacing this transistor, the sheet lets you confirm maximum drain-source voltage, drain current, dissipation and lead arrangement. Open it in any PDF viewer. Because pin order differs between packages and makers, check it against the board footprint before soldering in a substitute.
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.