A 40.7 KB PDF bearing the 2SC5451 part number. Under the JIS 2SC convention it is an NPN bipolar transistor, and the document is probably its datasheet even though the index category says schematic. Typical content covers terminal layout, package drawing, absolute maximum ratings and gain figures. Use it during repair to verify a part, confirm the pins before taking meter readings and choose a compatible substitute with matching package and equal or higher 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.