karabiner.json

{
  "title": "Map Hyper + d to F12",
  "rules": [
    {
      "description": "Map Hyper + d to F12",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "d",
            "modifiers": {
              "mandatory": [
                "right_command",
                "right_control",
                "right_option",
                "right_shift"
              ]
            }
          },
          "to": [
            {
              "key_code": "f12"
            }
          ]
        }
      ]
    }
  ]
}