@m0xee @Hyolobrika @mangeurdenuage Bluetooth headphones do need software to work, otherwise they couldn't handle the bluetooth protocol, receive the digital audio packets and decode them into an analogue signal.

The spying software in question runs on the demon rectangles and does settings changes and also updates the software on the headphones (the software update functionality makes the headphones a computer and that computer is absolutely proprietary).

I like headphones that work (i.e. headphones free of proprietary software), thus I use analogue headphones.