Karabiner-fn-hyperkey.json

{
    "description": "Fn Key → Hyper Key (⌃⌥⌘)",
    "manipulators": [
        {
            "from": {
                "key_code": "fn",
                "modifiers": { "optional": ["caps_lock"] }
            },
            "to": [
                {
                    "key_code": "right_command",
                    "modifiers": ["right_control", "right_option"]
                }
            ],
            "type": "basic"
        }
    ]
}