There's something else weird about that traveler system. The line they're measuring presumably came from Bora's boat. It's orange. The line shown going into the traveler cleat (again assuming this is the same boat in question) is green and looks like the tail of the mainsheet. However, I think I see that orange line at trampoline level just in front of the rear beam. I'm really interested in what that traveler control looks like.

It looks like the green line swaps into a split tail small diameter orange line and goes through the two sheaves in the traveler car (split tail on the mainsheet like normal). However, instead of tying off to two points centered on the rear beam (which I've always hated), it looks like they go out to the each end of the beam, turn, and then dead end back on either side of the traveler. I wonder if the orange line either tensions that system, offsets the end turning blocks somehow, or allows the traveler to pull to windward? The orange line is definitely tapered to be operated by hand - and the blue small diameter tail coming out of it appears to be doubled up - like it too is a split tail.....so I'm still confused.