I am aware of the fact that this feature is in development for PHP and Node.js, however it will be nice to also display the Java current source.
I am also aware of the fact that the code that is being deployed is a compiled version of the classes however I would suggest to add a field in the runner.properties file in which you would specify the source code of the server and simply displaying it in the same way you display the code in the generation tree.
Not only this will help developers keep track of the current code, but also in cases where the original source was deleted or lost, you can simply download the current code / view it.