Previously, TestCases could only be run through the DiffKit project. You needed to download the source code, have groovy installed, and then figure out how to invoke the TestCaseRunner.
Now, the standalone executable diffkit-app.jar carries the whole TestCase suite with it. All TestCases can be executed in place simply:
java -jar diffkit-app.jar -test
So now it's very easy for us to collect end-user supplied validation of the kit from different environments.