The reference active BR/EDR sniffer on commodity ESP32 hardware (~$4–10; ~590 stars, GPL-2.0). It patches the ESP32 ROM Bluetooth stack to dump baseband packets — BT header, channel, device role, FHS, ACL and LMP — over USB serial to a host Python tool (BTSnifferBREDR.py) with Scapy/Wireshark output. This is Bluetooth CLASSIC (BR/EDR), not BLE. It actively connects to the target, so authorised testing only.