On Sun, Apr 2, 2017 at 4:13 PM, Johnson Lau via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

>         • the witness of the first input of the coinbase transaction MUST
> have exactly one stack item (the "extended header"), with the following
> data:
>                 • bytes 0 to 3: nHeight MUST be equal to the height of
> this block (signed little endian)
>

 Someone told me a while back that it would be more natural if we move the
nHeight from the coinbase script to the coinbase locktime.  Have you
considered doing this?