This is according to the first link I posted:

The system is absolutely network-silent except when you actively do something that requires network access, like using the browser. It does not call the mothership, not for updates, not for telemetry, not to let Kim Jong Un know the status of your internal organs. Spoiler, he doesn’t give a fuck about your hentai porn. You’re not trusting me? Well, you should, because if you listened and installed the OS inside a VM, you can now mitm/firewall the external connections and notice the absolute silence.