Examine source code of 365Customizer

{
  "name": "365Customizer",
  "description": "Adds chosen tennis markets to favourites",
  "version": "1.1.0",
  "manifest_version": 3,
  "permissions": [
    "scripting",
    "activeTab",
    "storage",
    "cookies"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "365customizer_all@gmail.com"
    }
  },
  "action": {
    "default_title": "365Customizer",
    "default_popup": "popup.html"
  },
  "icons": {
    "20": "365.jpg"
  }
}