Examine source code of Switch

{
  "manifest_version": 2,
  "name": "Switch",
  "version": "1.1.0",
  "description": "Quickly switch between open tabs.",
  "icons": {
    "48": "icons/toggle-48.png",
    "96": "icons/toggle-96.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_title": "Switch",
    "default_icon": "icons/toggle-48.png",
    "default_popup": "panel/palette.html"
  },
  "background": {
    "scripts": [
      "selector/warden.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "switch@ducgiap.addon",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "description": "Switch does not collect any data."
      }
    }
  }
}