Examine source code of Hack This Website

{
  "manifest_version": 2,
  "name": "Hack This Page",
  "description": "This extension makes any webpage editable!",
  "version": "2.0",
  "icons": {
    "16": "assets/img/icon16.png",
    "48": "assets/img/icon48.png",
    "128": "assets/img/icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_action": {
    "default_icon": "assets/img/icon.png",
    "default_popup": "popup.html"
  }
}