Examine source code of Medium scroll to top

{
  "manifest_version": 3,
  "name": "Medium scroll to top",
  "version": "1.0.0",
  "description": "Adds a scroll to top button at right-bottom of all medium based sites.",
  "icons": {
    "16": "img/icon16.jpg",
    "32": "img/icon32.jpg",
    "48": "img/icon48.jpg",
    "64": "img/icon64.jpg",
    "96": "img/icon96.jpg",
    "128": "img/icon128.jpg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "app.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "medium-scroll-to-top-1@xatta-trone.com"
    }
  }
}