Datasheet-style PDF for the 2SD1423, 41.0 KB, stored as a schematic; the trailing _E in the name is not explained by the file itself. JIS rules give the 2SD prefix to NPN transistors intended for low-frequency use. The practical value lies in confirming emitter, base and collector positions, reviewing collector voltage and current limits and noting hFE classes. Open it in any PDF viewer, and when locating the part on a board look for D1423, as the 2S is normally omitted.
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.