You can sometimes see a similar approach in somewhat recent (~last 10 years) microcontroller devboards. Many of Nucleo devboards for STM32 microcontrollers, an

You can sometimes see a similar approach in somewhat recent (~last 10 years) microcontroller devboards. Many of Nucleo devboards for STM32 microcontrollers, and some Cypress PSoC devboards (CY8CKIT) consist of two halves. One containing the main MCU (the one devboard demonstrates), and other half containing programmer/debugger. Idea is that you can use it as is out of the box for running basic example programs, or you can break it in half thus obtaining a cheap programmer + devboard which has a slightly more convenient format for embedding in product prototype. Similar thing but reversed roles with ChipWhisperer-lite (platform for experimenting with side channel power analysis and glitching attacks). There you have the main board which connects to PC and performs the IO for attack and example target (victim) board. But all of that is for R&D purpose only, not for use in manufacturing of final products. I looked up the images for Starfox PCB it looks weird. Can't imagine it ever being practical in production just for programming. Did they just shipped devboards to customers? In the images I saw the area near PCB edge where traces stop looked very smooth and somewhat recessed compared to broken tabs that were connecting PCB to bigger panel. As if that area was cut by router instead of being broken off. Maybe they just kept the production PCB design (almost) identical to devboards, to save the work designing two different PCBs and reduce the chance of any issues caused by differences between devboards and production PCBs.