TL;DR
Ângelo Moisés Alves developed a passive USB 1.1 packet sniffer called USBSnifferPIO_RP2040, utilizing the Raspberry Pi RP2040 microcontroller's PIO (Programmable Input/Output) coprocessor. This device is designed to capture Low-Speed (1.5 Mbps) and Full-Speed (12 Mbps) USB traffic without any interference, meaning that the devices on the USB bus won't even detect its presence.