Examine source code of Clock theme

{
  "description": "Day and Night theme",
  "manifest_version": 2,
  "name": "Day and Night theme",
  "permissions": [
    "alarms",
    "theme"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "version": "1.1resigned1",
  "applications": {},
  "browser_specific_settings": {
    "gecko": {
      "id": "{557e5055-f731-40ed-aa35-40dc427d77ef}"
    }
  }
}