Examine source code of Extra Large Toolbar

{
  "manifest_version": 2,
  "name": "Extra Large Toolbar",
  "version": "1.0",
  "description": "Bigger icons and spacing in the Firefox toolbar.",
  "permissions": [
    "theme"
  ],
  "browser_action": {
    "default_title": "Extra Large Toolbar",
    "default_popup": "popup.html"
  },
  "icons": {
    "48": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ce550e75-b1e6-41a9-9256-72b3e4c39f89}"
    }
  }
}