We currently have seven testing-related modules in Git:
All of these are related to testing the starter application and typically we only release them when the starter is also released. As such, it's a pain to manually keep versions in sync and release the modules one by one. This is one scenario where a single git repository would make sense.
Whether this should be the actual starter repository or a starter-testing one is something that is not set in stone, but the current situation is not optimal.