Examine source code of Bookmark Manager

{
  "manifest_version": 3,
  "name": "Bookmark Manager",
  "description": "Personal Bookmark Manager",
  "version": "5.3.0",
  "author": "kevin@bookmarkmanager.com",
  "permissions": [
    "activeTab",
    "contextMenus"
  ],
  "action": {
    "default_title": "Bookmark Manager",
    "default_popup": "index.html",
    "default_icon": {
      "16": "icon_16.png",
      "24": "icon_24.png",
      "32": "icon_32.png"
    }
  },
  "icons": {
    "16": "icon_16.png",
    "32": "icon_32.png",
    "48": "icon_48.png",
    "128": "icon_128.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "type": "module"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "firefox-addon@bookmarkmanager.com"
    }
  }
}