What great resource thank you !

This new thing is pretty cool :

    =USB4STREAM for streaming data with USB4=

    In addition to Thunderbolt networking, which was already supported, this release adds support for streaming data directly over a cable as well (USB4STREAM). It is very simple and basically just transfers raw packets from one host to another. The driver exposes /dev/tbstreamX devices on each side of the link that can be used to transfer data using regular filesystem operations such as read(2) and write(2):

    host1 # cat /dev/tbstream0
    host2 # echo hello > /dev/tbstream0

    This can be useful in cases where network tooling is not available or just for existing applications like dd and cat that do not support sockets. This feature can be used at the same time with thunderbolt_net so they don't rule each other out, and it allows multiple streams to be created.