Examine source code of X Redirect

{
  "manifest_version": 2,
  "name": "X Redirect",
  "version": "1.2.1",
  "description": "Replaces all Twitter/X links with ones to xcancel.",
  "icons": {
    "48": "icons/logo_48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "x-redirect.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "x-redirect@example.com"
    }
  }
}