Examine source code of Good Day

{
  "manifest_version": 2,
  "name": "Good Day",
  "version": "1.0.1",
  "description": "Has a nice warm message every day.",
  "icons": {
    "48": "icons/48.png",
    "96": "icons/96.png"
  },
  "browser_action": {
    "default_icon": "icons/48.png",
    "default_title": "Good Day",
    "default_popup": "popup/goodday.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7d55609b-edda-4af4-9b83-323e1117fce0}"
    }
  }
}