nymea/libnymea/interfaces/extendedvolumecontroller.json

{
    "extends": "media",
    "states": [
        {
            "name": "mute",
            "type": "bool",
            "writable": true
        },
        {
            "name": "volume",
            "type": "int",
            "minValue": 0,
            "maxValue": 100,
            "writable": true
        }
    ]
}