Named simply 2SC5045, this 108 KB PDF appears under schematics, but the number follows JIS transistor naming where 2SC denotes an NPN bipolar device, so it is likely a datasheet. The name states no maker, package or revision. Its practical value lies in the pinout drawing, maximum ratings and characteristic curves used when checking a suspect transistor or picking a replacement. Make sure the code printed on the original part corresponds before trusting the data.
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.