[WUHANCLAN]

Bah there are several closed source plugins for Burp Proxy that are binary only and which constantly relay telemetry data back to Portswigger. I stopped using it for this exact reason, due to Burp Proxy's constant communication back to Portswigger. And the only thing that would need to be relayed back to Portswigger would be high value vulnerabilities that have been discovered.

Which would be trivial to implement as a covert channel in Burp Proxy's update process or any one of another methods of obfuscating and tunneling that data back to Portswigger.