API keys were always secrets. They control billing for heaven's sake. If you had any per-call billed APIs (like some of the voice processing APIs) enabled on t

API keys were always secrets. They control billing for heaven's sake. If you had any per-call billed APIs (like some of the voice processing APIs) enabled on the project then they're effectively keys to your pocket book. Otherwise they're a key tool to manage denial-of-service attacks.