Where can I find the material RoofVegetation in OpenStudio?

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I have to simulate a green roof in EnergyPlus. To do this, I'm using the interface OpenStudio for designing the house. I've read multiple times already that EnergyPlus has a material RoofVegetation which can be used for simulating a green roof, however, I can't find this material in OpenStudio. I also checked the 'Building Component Library', but I can't see it...