Number of live (non-terminated) VMs this key is attached to. Zero means the key is not scoped to any VM. The dashboard shows an "in use" indicator and warns before deleting a key that is in use.
blockingVmsstring[]
Names of VMs for which this is the only key that still resolves to a live org key. Deleting the key is refused (409) while this is non-empty; attach another key to those VMs first.