Examine source code of Return Button

{
  "manifest_version": 2,
  "name": "Return Button",
  "version": "1.0.0",
  "description": "Adds a 'Return' button to any website, allowing users to go back one page in their browsing history.",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{39d9f24e-bbcf-4233-b71a-375dd71d4263}"
    }
  }
}