Examine source code of twicord embed

{
  "manifest_version": 2,
  "name": "twicord embed",
  "version": "1.1",
  "description": "automatically replace x.com / twitter.com post links with fxtwitter.com when you copy a link on the site",
  "icons": {
    "48": "icon-48.png"
  },
  "permissions": [
    "clipboardWrite"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://x.com/*",
        "*://*.x.com/*",
        "*://twitter.com/*",
        "*://*.twitter.com/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_icon": {
      "48": "icon-48.png"
    },
    "default_title": "twicord embed"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "fxtwitter-copy@example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}