Datasheet PDF for the 2SC4405, 113 KB in size. The name holds only the part number, and the JIS 2SC prefix tells us it is an NPN bipolar transistor rather than a board. Such a document is consulted for absolute maximum ratings, gain and saturation figures, plus the package outline and lead order, all of which matter when replacing a failed device. Open it in any PDF reader and compare the marking on the original transistor with this number before choosing a replacement.
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.