RE: Hello, I'm new here and this is me :-)

It's the alkaline solution you bathe it in. NaOH- or Sodiumhydroxide is the best to use, as you can use it in cold water. You can also use Sodium Bicarbonate/baking soda (not baking powder), but you have to heat that one up until boiling and then keep up the high temperature in at least 30seconds bathing each side, which accelerates the rising process of the yeast.
But that's basically all there is - the dough is just a regular white-bread-dough, maybe a little less hydration than a regular baguette. We use 300g Water on 500g flour, plus 10g of oil or fat of your choice - more or less, there's always some regulating thing that the main baker does when sensing the dough :-D