Other examples of proprietary malware
Patent applications show that Google and Amazon are interested in making “digital assistants” study people's activities to learn all about them.
AI programs would understand what people say to each other, observe the clothing they wear and the objects they carry (including the marketing messages on them), and use sound to track people's activities, including in the toilet or in bed.
It should be illegal to have such a device in your apartment without getting signed consent from the people that live in the other appartments in the building.
Any device that has a microphone and a speaker could be turned into a sonar system that would track the movements of people in the same room or other rooms nearby.
This page describes malicious techniques that proprietary software might use in the future for malicious purposes. We don't have any evidence that they are in use yet.