Examine source code of Autofocus

{
  "manifest_version": 2,
  "name": "Autofocus",
  "description": "Search faster - Puts the cursor in the search box on page load",
  "version": "0.2",
  "icons": {
    "16": "img/icon-16.png",
    "48": "img/icon-48.png",
    "128": "img/icon-128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "contextMenus"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_script.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "Autofocus",
    "default_popup": "popup/popup.html"
  },
  "options_ui": {
    "page": "options/options.html",
    "browser_style": true,
    "chrome_style": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "autofocus@adrianh.net"
    }
  }
}