[nos-bbs] curious address formation in AX.25 network

[(Skip) K8RRA]

Greetings.

I have run into a situation I can't find documented (yet).

Here is the model:
There are 2 sites, K8RRA (mine) and N8FQ (a forwarding partner).
There are 3 users, K8RRA (me), N8FQ sysop, and KD8BHV a friend.

Here is the timeline:
KD8BHV logs in to N8FQ and "send k8rra" followed by title and message.
Later N8FQ sysop "mbox kick k8rra" and sees no confirming messages.
Later still I read the message with the addresses:
  FROM: KD8BHV%N8FQ.bbs at K8RRA.AMPR.ORG
    TO: K8RRA at K8RRA
at my own K8RRA site.  Now I'm confused...

In reading my document collection, I find some references to the KD8BHV%
N8FQ syntax in in the TO: address, and I appreciate the "%" delimiter
meaning.  What I don't find is:
 A) how the FROM: syntax was handled by jnos:
	from the original KD8BHV at N8FQ 
	to the delivered KD8BHV%N8FQ at K8RRA (K8RRA as fully qualified for TCP/IP
network.)
 B) In addition, I find no reference to where the N8FQ suffix ".bbs"
originated.
 C) Even stranger is that FROM: carries an "@K8RRA" suffix when it
actually originated at N8FQ.

It's clearly MAGIC!

Neither N8FQ nor K8RRA have any rewrite or alias rules to create any
syntax containing "%", besides scanning doesn't mess with the message
itself (which I *presume* includes the FROM: and TO: fields).

SO --  can anyone tell me:
What are the "rules" governing FROM: address by jnos?
What significance is given to ".bbs" that a user must know?
Is our experience correct [I should add it to jnos wiki]?

73
de [George (Skip) VerDuin] K8RRA k