Examine source code of Toolbar hour

{
  "manifest_version": 2,
  "name": "Toolbar hour",
  "version": "1.2",
  "description": "Displays a hour in the toolbar.",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "hour"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{967f4c67-a20a-429b-bc77-3f3ba3c7675f}"
    }
  }
}