Examine source code of Custom Backgrounds

{
  "manifest_version": 3,
  "name": "Custom Backgrounds",
  "version": "1.0",
  "description": "تغيير خلفية المواقع بصور مخصصة",
  "permissions": [
    "storage",
    "activeTab",
    "unlimitedStorage"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "action": {
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "custom_backgrounds@yourdomain.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}