PDF data sheet, about 135 KB, covering the 2SC4540 transistor. Under JIS semiconductor numbering the 2SC prefix identifies an NPN bipolar device, so the document should hold electrical characteristics, absolute maximum ratings and a package drawing. Although it is filed as a schematic, no board or device is named. Technicians use such sheets to pick a substitute part, confirm which leg is base, collector or emitter, and judge whether a failed transistor was overstressed in circuit.
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.