stub zones

[Tim Maestas]

When you set up a zone of type stub, when the zone is loaded what method
does named use to get the NS records and any corresponding glue from the
server listed as master?  In the zone file that is created on the stub
server after starting the server, it says:

; zone 'foo.com' first transfer
; from 192.168.1.1:53 (local 192.168.1.2) using AXFR at <date>

This would lead me to believe that it used AXFR to transfer the records.
But AXFR would transfer the whole zone, not just the NS records.  Besides
which I see nothing in the master server's logs to indicate any kind of
zone transfer took place.  And if I don't allow the stub server's IP in
allow-transfers, it still is able to get the NS records.  Is it just doing
an SOA query on the master and getting the NS and glue records from that?
If this is what's happening, why does it say "using AXFR" above?

Thanks.

-Tim Maestas