Examine source code of Video Flipper

{
  "manifest_version": 2,
  "name": "Video Flipper",
  "description": "Video Flipper for YouTube and DailyMotion",
  "version": "3.4",
  "icons": {
    "48": "icons/mirror-48.png",
    "96": "icons/mirror-96.png"
  },
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{032629b6-ae13-4f11-9bcb-0596ba290247}"
    }
  }
}