Covering the 2SD1193, this 135 KB PDF is indexed as a schematic but its name identifies a discrete component, so it is most likely the maker's datasheet. JIS numbering assigns 2SD to NPN bipolar transistors for low-frequency applications. Expect maximum ratings, characteristic tables and the outline drawing inside. Use it to verify the pin arrangement and gain class before soldering in a part. Checking the junctions with a diode-test meter tells you whether the original actually needs replacing.
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.