A complex modification rule for Karabiner Elements to enable the use of Escape as both Esc and Ctrl

escape_multifunction.json

{
  "title": "Escape Multifunction",
  "rules": [
    {
      "description": "Change Esc to both Esc and Control",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "escape",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "left_control",
              "lazy": true
            }
          ],
          "to_if_alone": [
            {
              "key_code": "escape"
            }
          ]
        }
      ]
    }
  ]
}