[crb]

It might help to think of it like this.

Kubernetes is an engine with some built-in data types and controllers for some common container use cases (N replicas, 1 replica per node, etc). These are released along with the project on a quarterly cadence.

You can also add your own data types and controllers. The combination of these things is sometimes branded an "operator" if it controls a certain piece of software. You can release and manage these yourself on your own timeline, decoupled from Kubernetes releases.