Im curious now since I havent used North yet.
In the part of the 2012 trust bar manual I referenced, in section 6.1.3, they refer to a section of line called "a". It is a piece tied to the LE of the kite to the ring on the bar. If that is not the nose line, what is that piece of line called?
Here is a link to the manual?
... the manual doesn't show the nose line, its does show the "5th line" and this line goes all the way from the safety ring under the chicken loop, through the bar, continues through the ring and ends with the "a" referred in manual. This 5th line is then attached the the nose line to complete the whole ""5th line"". A stopper ball under the ring stops the line from pulling through so it doubles as a support for the LE (hence why they call the Rebel/Vegas/Torch a loaded 5th line kite).
You could call the nose line as another bridle that happens to be attached to the center of the LE, only its a simplified bridle with one or some times 2 attachment points.
see the thicker looking line on the LE, that's a nose line:
you can see the orange rebel has a double nose line:
this diagram is a 5th with a Y on LE, such as above rebel:
this diagram is a single nose line attachment, like my Dyno:
here is a simplified pic of a north bar and its the line labled 6 in diagram that attaches to the nose line, or "a" in your reference to north manual:
clear as mud??