A 110 KB PDF named after the part number 2SC3456, catalogued as a schematic but more likely a component datasheet. The JIS scheme assigns the 2SC prefix to NPN bipolar transistors. Repair technicians use these sheets to identify pins, read collector current and breakdown voltage ratings, and evaluate equivalents from cross-reference tables. The name gives no manufacturer, package or grade, so compare the printed marking, usually C3456, and the case outline with the part on your board.
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.