We've known about Debug-USB for a while [1] and suspected that the new "dockchannel UART" ends up there somehow. Turns out, at least macOS 26 just comes with a driver for this: After switching the port to the correct mode [2] /dev/cu.kis-100000-ch-0,1,2 and 3 appear and the first one indeed is the other end of that new UART!
Now we just need to sniff USB and actually implement the protocol and then we get a very cool low-level UART without any additional hardware since we can enter this mode directly on the device from m1n1!
[1] https://asahilinux.org/docs/hw/soc/usb-debug/
[2] https://github.com/AsahiLinux/tuxvdmtool/commit/44682921ace2790f543554818b00e19ee87694ba
