Greetings!

*** John Goerzen [2023-10-30 17:07]:
>The niceness in the outer header (encrypted packet header) is 96, while
>in the inner plain header it is 224.

Those are independent niceness levels.
As http://www.nncpgo.org/Plain.html says, inner (plain packet's)
niceness is a value passed to $NNCP_NICE when invoking exec-script.
In freq-packets it is used as a nice to generated file-packets in reply.
Outer niceness is used only during transmission. Inner one depends on
packet's type and used during tossing, when dealing with plain packet.

>Also, the payload type is 3 rather than 2.  I wonder if the payload
>types start at 1 instead of 0?

Yes, it starts with 1.

-- 
Sergey Matveev (http://www.stargrave.org/)
OpenPGP: 12AD 3268 9C66 0D42 6967  FD75 CB82 0563 2107 AD8A