Examine source code of Flip videos

{
  "manifest_version": 2,
  "name": "Flip videos",
  "version": "0.0.4",
  "description": "Flip all videos on page",
  "icons": {
    "32": "icon-32.png",
    "64": "icon-64.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "contextMenus",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a571db78-8ceb-4dae-b004-8a804392532c}"
    }
  }
}