No, I do not have any documentation on this nor do I expect any documentation from the likes of Qualcomm where they claim not to exfiltrate data without prior agreement to be all that convincing. What I do have is experience in using firewalls on Android devices for as long as I've used those (about 12 years). I regularly use packet sniffers to see what these devices send to the 'net both to check whether my own stuff is working OK and to check for unwanted traffic. Setting the firewall to block outgoing traffic before enabling network connectivity has always been effective, this includes devices using Qualcomm modems. I use WiFi for these tests just like described in the article as testing for unwanted traffic going over the 3/4/5G connection is only possible if you have a private 4/5G network which I do not (yet) have. I tend not to use 3/4/5G data though - I only have a single device on which I have data enabled and paid for, the rest goes through life using only WiFi. If Qualcomm has made a deal with all mobile operators to push their telemetry through 3/4/5G even on accounts which have data disabled (as in 'not paid for' as well as 'function disabled in Android') they're in for a world of hurt when that news is brought to the light. I assume they have no such agreements as it would not make any sense seeing how easy it is to just use Android and iOS to push that data back to the mothership - which seems to be what they are doing. They are far from the only ones doing this, it is actually the main reason why I block outgoing traffic by default. Just give it a try sometimes, take a device and hook it up to the network through WiFi. Use a packet sniffer on the router to intercept everything coming from that device and feed the result to something like Wireshark. Do the same with that device with a firewall filtering all outgoing traffic and compare the results.