Examine source code of YouTube Open as Embed

{
  "manifest_version": 2,
  "name": "YouTube Open as Embed",
  "version": "1.4",
  "description": "Gives a right-click menu option to open a youtube video as an embed. (full window, faster)",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "menus"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{6b88683c-1596-4245-8c4e-2ab83918db3c}"
    }
  }
}