Compact 32.8 KB PDF labelled 2SC5645, filed among schematics but most probably a single-part datasheet for that transistor. JIS numbering assigns 2SC to NPN bipolar transistors, originally high-frequency types. The name carries no manufacturer, package or revision detail. A short sheet like this usually covers ratings, key characteristics and the outline drawing, enough to verify pinout and limits during a repair. SMD parts often carry abbreviated codes, so cross-check the marking on the board against the document before replacement.
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.