Examine source code of Touch Navigate

{
  "manifest_version": 2,
  "name": "Touch Navigate",
  "author": "ShimmyMySherbet",
  "version": "0.1",
  "description": "Adds touch screen swipe navigation to navigate back and forth. Designed for navigation with 2-in-1 laptops in tablet mode.",
  "icons": {
    "48": "assets/icon-48.png",
    "96": "assets/icon-96.png",
    "128": "assets/icon-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "js/navigate.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "touchnavigate@shimmymysherbet.com"
    }
  }
}