Examine source code of Responsify viewer

{
  "manifest_version": 2,
  "name": "Responsify",
  "version": "0.1",
  "description": "A simple slider to check the responsivness of the website.",
  "icons": {
    "96": "icons/icon-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "content_scripts/responsify.js"
      ]
    }
  ],
  "permissions": [
    "tabs",
    "<all_urls>",
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_title": "Responsify",
    "default_icon": "icons/browser-96.png",
    "default_popup": "popup/slider.html"
  },
  "author": "Karthikeyan Rajendran"
}