PDF document of 331 KB named after the 2SC4116 part number, filed in the index under schematics. The 2SC prefix follows the Japanese JIS/JEITA designation for NPN bipolar transistors intended for high-frequency use, so the content is most likely a component datasheet rather than a board diagram. Technicians use such sheets to confirm pinout, package marking, maximum ratings and equivalents before replacing a failed part. Compare the SMD marking code on the board with the one listed before ordering.
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.