Examine source code of PageExplorer

{
  "name": "PageExplorer",
  "description": "PageExplorer helps you to optimize your website's SEO potential, page by page.",
  "version": "1.1.1",
  "manifest_version": 2,
  "icons": {
    "48": "icons/icon_trans_48.png",
    "96": "icons/icon_trans_96.png",
    "128": "icons/icon_trans_128.png"
  },
  "browser_action": {
    "default_title": "PageExplorer",
    "default_popup": "popup/popup.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "options_ui": {
    "page": "options/options.html",
    "chrome_style": true
  },
  "content_scripts": [
    {
      "matches": [
        "http://dev.pageexplorer.net/*",
        "https://pageexplorer.net/*",
        "https://next.pageexplorer.net/*"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "<all_urls>"
  ]
}