Examine source code of Custom Css Insert Dev

{
  "manifest_version": 3,
  "name": "Custom CSS Injector",
  "version": "1.0",
  "description": "Custom CSS Injector: Injects user-defined CSS.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": "custom_css_injector.png"
  },
  "icons": {
    "128": "custom_css_injector.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "thomasadams5965@outlook.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}