How crunchydata Postgresql operator and Service works

Question

We have deployed a PostgreSQL with crunchydata operator. We followed the link https://access.crunchydata.com/documentation/postgres-operator/v5/quickstart/#connect-using-a-port-forward and connected with port-forward successfully to pods. Further, our services works and connect to Databases through Service created.

My question is:
Service that created is with name my-test-db-primary. This service has no pod selector, however the pods are connecting while port-forward not. How this works and how it knows the destination?

kind: Service
apiVersion: v1
metadata:
  name: my-test-db-primary
  namespace: test-databases
  labels:
    postgres-operator.crunchydata.com/cluster: my-test-db
    postgres-operator.crunchydata.com/role: primary
  ownerReferences:
    - apiVersion: postgres-operator.crunchydata.com/v1beta1
      kind: PostgresCluster
      name: my-test-db
      controller: true
      blockOwnerDeletion: true
spec:
  ports:
    - name: postgres
      protocol: TCP
      port: 5432
      targetPort: postgres
  clusterIP: None
  clusterIPs:
    - None
  type: ClusterIP
  sessionAffinity: None
  ipFamilies:
    - IPv4
    - IPv6
  ipFamilyPolicy: RequireDualStack
  internalTrafficPolicy: Cluster
status:
  loadBalancer: {}

Answer 1

Further reading the k8s documentation Documentation

Quoting from Documentation:

When you create an EndpointSlice object for a Service, you can use any name for the EndpointSlice.

Each EndpointSlice in a namespace must have a unique name. You link an EndpointSlice to a Service by setting the kubernetes.io/service-name label on that EndpointSlice.