Examine source code of backNforward

{
  "manifest_version": 2,
  "name": "BackNForward",
  "version": "1.0",
  "description": "Allows a user to use two finger swipe on the touchpad to move back and forward between pages",
  "icons": {
    "48": "arrows.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "moveTo.js"
      ]
    }
  ]
}