Examine source code of Fullscreen Toggle Button

{
  "manifest_version": 2,
  "name": "Fullscreen Toggle",
  "version": "1.1",
  "description": "Adds a button to toggle fullscreen mode.",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "96": "icons/icon96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Fullscreen Button Settings",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bd2c2d81-9ce5-4620-b13a-775741b65682}"
    }
  }
}