You can make a copy of an existing App by reusing the App's configuration files and manually porting Secrets.
You might want to copy an application if:
You use feature branches for development. Use a unique copy of the App for each feature branch to avoid conflicts.
You run tests against a working version of the App. You can copy an App for each test run to to ensure a consistent start state.
You deploy the same app to clusters across regions using a local deployment model. You can copy an App to serve multiple regions locally.