Examine source code of CP Calendar

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "CP Calendar",
  "description": "An extension that keeps users updated about Coding or Competitive Programming contests.",
  "version": "1.0.0",
  "manifest_version": 2,
  "browser_action": {
    "default_popup": "index.html",
    "default_icon": "logo/128.png"
  },
  "icons": {
    "16": "logo/16.png",
    "48": "logo/48.png",
    "128": "logo/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7c3992c0-3c8a-4c48-baac-51b3e8771256}"
    }
  }
}