Examine source code of Quick Simple Calendar

{
  "manifest_version": 2,
  "name": "Quick Simple Calendar",
  "version": "1.0",
  "description": "View a small monthly calendar in popup.",
  "icons": {
    "64": "icon64.png",
    "128": "icon128.png"
  },
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon64.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{cb832a40-3ea6-4fe9-8b04-79cf1b84de2b}",
      "strict_min_version": "125.0"
    }
  }
}