The BWD menu itself is made using the forthcoming MenuLab stacks but the scroll appearance of the main menu is simply done with Chroma Pro.
Basically, it is a Chroma with a menu and a hamburger in it. The menu is set to be hidden until the first chroma marker is encountered. It could be replicated in many ways but the main menu could be a Foundation TopBar, a Foundry Nav Bar, a MagicGellan2 or one of the other menu bar stacks available. The burger menu component could be done with a PopDrop Menu, a Limelight Menu or any other burger / overlay menu that is capable of being set to static position (this is important as it must be Chroma that does the fixed position).