Examine source code of UniversalNotes

{
  "manifest_version": 3,
  "name": "UniversalNotes",
  "description": "Bringing Community Notes from Twitter to every website.",
  "version": "1.4.2",
  "action": {
    "default_popup": "popup.html",
    "default_title": "UniversalNotes",
    "default_icon": "icon128.png"
  },
  "permissions": [
    "tabs"
  ],
  "host_permissions": [
    "*://*.universalnotes.org/*"
  ],
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "options_page": "options.html",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "universalnotes-firefox@universalnotes.org",
      "strict_min_version": "110.0"
    }
  }
}