[inventor7777]

That is fair. I do not think anyone could feasibly could detect/extract the exact data sent, because of HTTPS.

However I was more thinking of simple things, such as disabling anything that SHOULD be communicating with the Internet and seeing if any constant traffic persists.

Now of course, some very small (e.g plaintext) traffic might be almost undetectable, however that would suggest that most of the data would not be able to be transmitted due to size.