Change caps_lock to command+control+option+shift or F19 if tapped.

custom-capslock.json

{
  "title": "Change caps_lock to command+control+option+shift or F19 if tapped",
  "rules": [
    {
      "description": "Change caps_lock to command+control+option+shift or F19 if tapped",
      "manipulators": [
        {
          "from": {
            "key_code": "caps_lock",
            "modifiers": {
              "optional": ["any"]
            }
          },
          "to": [
            {
              "key_code": "left_shift",
              "modifiers": ["left_command", "left_control", "left_option"]
            }
          ],
          "to_if_alone": [
            {
              "key_code": "f19"
            }
          ],
          "type": "basic"
        }
      ]
    }
  ]
}

usage.sh

curl https://gist.githubusercontent.com/matthewmueller/6b6cc31e7789c717ab9bb55284e0557b/raw/a4c8a7fa0bedd8198526d068fc75190df4aeb271/custom-capslock.json > ~/.config/karabiner/assets/complex_modifications/custom-capslock.json