Phx 1.7.0-rc0 LayoutView? put_root_layout ? (documentation mismatch maybe)

The documentation for 1.7 rc0 mentions a LayoutView module in a number of places, but that module doesn’t exist in my generated 1.7 apps. For instance, the documentation exemplifies :put_root_layout as:

plug :put_root_layout, {HelloWeb.LayoutView, :root}

Is the intention that HelloWeb.LayoutView, be replaced by HelloWeb.Layouts ? And if not, what should be the content of that LayoutView in 1.7? It used to be use MyAppWeb, :view but the view() function doesn’t exist anymore in my_app_web.ex.

(FWIW my actual issue is using :put_root_layout idiomatically in a 1.7 app.)