Ha! I spent a bunch of time on that last night myself! I think it’s fascinating that they tried so many auto sexing mixes using the barring gene!I had to look it up. Here is what I found:
Origin of the Cream Legbar
The Cream Legbar is a cross between Barred Plymouth Rocks and Brown Leghorns, with some Araucana and Gold Campine genes. The Araucana genes give the Cream Legbar its funny little crest and the sky-blue or pale green eggs; the Leghorn contributed its excellent egg production (160 to over 200 per year); the Barred Plymouth Rock genes contribute the ability to easily tell roosters from hens when the chicks hatch.
So it is basically a mutt made up of 4 different breeds including the only two breeds I had understood were breeds - Leghorn thanks to @BY Bob and Campine thanks to @Ribh
I wonder if they will be crazy like the Campines or super friendly like the Leghorns. So far I would say both!