dotfiles/karabiner/assets/complex_modifications/custom-capslock.json

{
  "title": "Change caps_lock to Esc and Control",
  "rules": [
    {
      "description": "Post Esc if Caps is tapped, Control if held.",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "left_control",
            "modifiers": {
              "optional": ["any"]
            }
          },
          "to": [
            {
              "key_code": "left_control",
              "lazy": true
            }
          ],
          "to_if_alone": [
            {
              "key_code": "escape"
            }
          ]
        }
      ]
    }
  ]
}