You can view a private clusters endpoints using the gcloud command-line tool or GCP Console.
Run the following command:
gcloud container clusters describe [CLUSTER_NAME]
The output shows both the private and public endpoints:
...
privateClusterConfig:
enablePrivateEndpoint: true
enablePrivateNodes: true
masterIpv4CidrBlock: 172.16.0.32/28
privateEndpoint: 172.16.0.34
publicEndpoint: 35.239.154.67