Examine source code of Filmbol URL Extractor

{
  "manifest_version": 2,
  "name": "URL Extractor",
  "version": "1.0",
  "description": "Extracts URLs from the current page.",
  "permissions": [
    "activeTab",
    "scripting"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{055d98b9-81d7-4414-bd14-8a11a6c34b5f}"
    }
  }
}