This 463 KB PDF, named after the 2SC4315, is grouped with schematics, though a bare part number like this usually indicates a datasheet. In Japanese JIS numbering the 2SC prefix identifies an NPN bipolar transistor, with C4315 commonly printed on the case. Expect pin assignment, outline dimensions and electrical limits inside. Verify the physical package matches before trusting the pinout, and ensure any replacement meets or exceeds the original voltage, current and power ratings.
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.