A 143 KB PDF on the 2SC3649. Following Japanese JIS semiconductor numbering, the 2SC prefix marks an NPN bipolar transistor; the file name supplies only that number. Contents are likely a manufacturer datasheet with ratings, electrical characteristics and an outline drawing, not a full schematic. Consult it before substituting a failed part, matching pinout and package to the PCB footprint and making sure voltage, current and dissipation ratings equal or exceed the original.
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.