Examine source code of Tabs Manager Pro

{
  "manifest_version": 2,
  "name": "Tabs 101",
  "author": "francosang",
  "version": "1.0.0",
  "icons": {
    "16": "assets/browsers16.png",
    "48": "assets/browsers48.png",
    "64": "assets/browsers64.png",
    "128": "assets/browsers128.png",
    "256": "assets/browsers256.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true,
    "type": "module"
  },
  "browser_action": {
    "default_icon": {
      "16": "assets/browsers16.png",
      "48": "assets/browsers48.png",
      "64": "assets/browsers64.png",
      "128": "assets/browsers128.png",
      "256": "assets/browsers256.png"
    },
    "default_title": "Show Tabs",
    "default_popup": "index.html"
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b8d20c6a-c283-4837-9400-22a95888ed04}"
    }
  }
}