Examine source code of Tabson

{
  "browser_specific_settings": {
    "gecko": {
      "id": "{b8347bca-0d8d-40e8-bbb1-f0135ce45730}",
      "strict_min_version": "65.0"
    }
  },
  "manifest_version": 2,
  "name": "Tabson",
  "version": "1.4.1",
  "browser_action": {
    "default_popup": "tabson.html",
    "browser_style": true
  },
  "permissions": [
    "tabs",
    "downloads",
    "activeTab",
    "downloads.open"
  ],
  "icons": {
    "64": "icons/icon.png"
  }
}