Small PDF of 25.0 KB dedicated to the 2SC4064, catalogued as a schematic. Going by JIS semiconductor numbering, 2SC marks an NPN bipolar transistor; the name gives no other facts such as manufacturer or case style. A technician typically reaches for a sheet like this to verify pinout before probing, to read voltage and current limits, and to check whether an available part can stand in for a failed one. Make sure the device you are replacing actually carries this number, since marking codes can be shortened.
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.