Examine source code of Substack Notes Scheduler

{
  "manifest_version": 2,
  "name": "Substack Notes Scheduler",
  "version": "1.1.0",
  "description": "Schedule and auto-post notes to Substack",
  "homepage_url": "https://substack-notes-scheduler-backend.vercel.app",
  "browser_specific_settings": {
    "gecko": {
      "id": "substack-notes-scheduler@andromeda",
      "strict_min_version": "142.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "permissions": [
    "cookies",
    "storage",
    "alarms",
    "https://substack.com/*",
    "https://*.substack.com/*",
    "https://substack-notes-scheduler-backend.vercel.app/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_popup": "popup/index.html",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  }
}