Examine source code of Paint App Basic Fun

{
  "manifest_version": 2,
  "name": "Paint App Basic Fun",
  "version": "1.0",
  "description": "Paint App is an interesting utility that allows you to draw anything right on the widget when it turns on",
  "permissions": [],
  "browser_action": {
    "default_popup": "game.html",
    "default_icon": {
      "128": "images/pain-logo.png"
    }
  },
  "icons": {
    "128": "images/pain-logo.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{fdaff107-74bc-4e55-90f3-28f3b28ec14d}"
    }
  }
}