The 2018 Open Hardware Summit badge features an ESP32 microcontroller running MicroPython firmware. The firmware provides a Python interpreter prompt (REPL) on the serial port which allows interactive programming of the badge!
This post describes how to connect an FTDI 3.3V USB to serial cable to the J1 header on the badge. In addition to the serial console, this adapter board for the J1 header enable new MicroPython firmware to be flashed on to the badge.
Blog post: Open Hardware Summit badge: adapter board for USB-to-serial cable