Named 2SJ503, this 87.9 KB PDF is tagged as a schematic but most likely contains a transistor datasheet, because 2SJ is the Japanese JIS designation for P-channel field-effect transistors. The modest size suggests a brief sheet with ratings, characteristics and a package drawing. It helps when sourcing a replacement for a failed switch, checking pin order before soldering, or confirming voltage and current limits in a repaired circuit. The name gives no further detail, so compare the original part marking carefully.
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.