The 2SC4527 data sheet, a 310 KB PDF filed under schematics but in practice a component specification. JIS numbering uses 2SC for NPN bipolar transistors, so the file should list limits, typical curves and the mechanical outline. It helps when a transistor tests shorted or open and a correct replacement is needed. Compare voltage, current and dissipation ratings with any substitute, and match the case style and lead order shown in the drawing to the footprint on the PCB.
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.