Examine source code of xkcd Enhancer

{
  "manifest_version": 3,
  "version": "1.3",
  "name": "XKCD Enhancer",
  "short_name": "XKCD Enhancer",
  "description": "This extension displays an explain button on xkcd.com, and redirects to m.xkcd.com, if the device is mobile.",
  "icons": {
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{acde134d-dbc5-4f82-b7e6-8ce99d7883b5}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "*://xkcd.com/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.xkcd.com/*"
      ],
      "js": [
        "xkcd.js"
      ]
    }
  ]
}