As it turns out, the Apple TV 4K includes a hidden Lightning port. This discovery was first made on Twitter by Kevin Bradley, better known as nitoTV on Twitter. This could lead to access to the Apple TV 4K’s firmware.
While earlier Apple TV models had Micro USB and USB-C, the Apple TV 4K dropped all outwardly-facing ports other than Ethernet and HDMI. Under the hood, however, there’s a hidden Lightning port, as Bradley discovered.