The bit (no pun intended) I do not understand is why there is such a discussion in the first place? Why do they insist on a plaintext status bit?
Thats why I wondered if there was any encryption outside of the UDP payload.
Because it's just one bit and it can have two values and both are valid and both values are seen with about the same frequency, a middlebox won't be able to just drop a packet if the value is either 0 or 1.
This is why there is even a discussion happening. It's felt to be reasonably safe to include to provide some actual value to tools.
The debate is though whether it's really safe and/or whether it provides enough value to go through the trouble.
If you ask me personally, in my professional life, I have been bitten by protocol ossification way more than by not being able to make sense out of a packet stream, so I personally would absolutely not expose anything.
But then again, I'm an application level developer and not a network administrator.
> a middlebox won't be able to just drop a packet
You do know that someone somewhere is going to make a middlebox that just drops a packet unless that bit flipped in the precise sequence that the middlebox developer believed was the correct one, right?
Then someone proposes an enhancement to QUIC which happens to change the sequence of the flips (perhaps some multipath thing, or an enhancement in the way it treats reordered packets), and it breaks...