The Nest Hello device is a smart doorbell with an inbuilt camera. A leak concerning a software update for this product has found that it may gain the ability to detect when a package has been delivered. This code may also allow for a follow-up feature in which it can tell when the same has been picked up again.
https://www.notebookcheck.net/Nest-Hello-doorbell-to-get-delivery-monitoring-update.427227.0.html