The JupyterLab app makes it easy to add JupyterLab to a Project. All Default Base Environments come with JupyterLab pre-installed, so adding this app is only necessary if you are using your own custom container.
When you add the app to a Project, AI Workbench adds the Jupyterlab package to your environment, and configures a user-defined app in the spec.yaml file of the project.