Examine source code of CalSyncMaster

{
  "manifest_version": 2,
  "name": "CalSyncMaster",
  "version": "1.0",
  "description": "Synchronize your calendars seamlessly with CalSyncMaster.",
  "permissions": [
    "identity",
    "https://your-authentication-url.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "images/icon16.png",
    "48": "images/icon48.png",
    "128": "images/icon128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2a313ffe-6d50-44e3-92f5-4afa9a860068}"
    }
  }
}