Berkeley DB is a well-known open source embedded database. We suspect that most users never really even look at the sources, but that they do like knowing that they can if they ever want to. Others may want to look over the sources just to see if the code looks clean -- kicking the tires so to speak. And then there are the users who actually find bugs for us. This recently happened. A user was getting a BufferOverflowException while using JE and since he had a reproducible case he went ahead and diagnosed it for us. His analysis took us straight to the actual problem and we'll be issuing a patch shortly (3.3.82).