Bramus Van Damme covers that the spec now includes some new values:
The “Large Viewport”: lvh / lvw / lvmin / lvmax
The “Small Viewport”: svh / svw / svmin / svmax
The “Baby Bear Viewport”
The “Dynamic Viewport”: dvh / dvw / dvmin / dvmax
The Dynamic Viewport is the viewport sized with dynamic consideration of any UA interfaces. It will automatically adjust itself in response to UA interface elements being shown or not: the value will be anything within the limits of 100vh (maximum) and 100svh (minimum).