DataLex is an online tool for converting legislation into encodings, and using those encodings to generate a web-based chatbot interface that can hold a conversation with a user, answer a question, and provide an explanation for that conclusion. It is free for non-commercial use, and closed-source.
It’s underlying reasoner and language, YScript, is open source.
According to this paper, the scripting language YScript on which DataLex is (recently) based is available under the Affero open source license. So it seems that the front-end tool which generates the chatbot interface in DataLex may be closed source, but that the underlying reasoner may now be available. Source code is only available currently from the author Andrew Mobrey, but a public repository is expected soon.