Examine source code of Clock

{
  "manifest_version": 2,
  "name": "__MSG_lngExtTitle__",
  "version": "1.1.0.0",
  "description": "__MSG_lngExtDescription__",
  "default_locale": "en",
  "permissions": [
    "storage",
    "scripting",
    "tabs",
    "alarms",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "css/content.css"
      ],
      "js": [
        "scripts/content.js",
        "scripts/clock.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "images/skins/*.png",
    "fonts/*"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon16.png",
      "32": "images/icon32.png",
      "48": "images/icon48.png",
      "128": "images/icon128.png"
    }
  },
  "icons": {
    "16": "images/icon16.png",
    "32": "images/icon32.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{e66b9769-5e03-4637-828b-bd5bd2eb2c1b}"
    }
  }
}