Indexed under schematics, the 197 KB PDF for the 2SC5460 is most probably a full datasheet for this NPN transistor from the Japanese 2SC series. Such documents provide ratings, electrical characteristics, safe operating area or derating graphs, and package dimensions. A technician uses it to verify whether a part on the board has failed, to cross-reference replacements and to confirm the emitter, base and collector positions. Compare the voltage and current limits carefully before fitting any alternative part.
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.