Named after the 2SD2093, this PDF of 146 KB is most likely the component datasheet for that Japanese transistor. In the JIS system, 2SD indicates an NPN bipolar device rated for low-frequency operation. The document typically supplies absolute maximum ratings, characteristic curves, gain classification and a dimensioned package drawing. Technicians rely on it to pick a safe replacement and to locate the collector, base and emitter leads correctly. Read the marking on the original part closely to confirm the code before swapping it.
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.