Examine source code of XKCD Newtab

{
  "description": "Replaces your newtab with a random xkcd",
  "manifest_version": 2,
  "name": "XKCD Newtab",
  "version": "1.1resigned1",
  "homepage_url": "https://github.com/simplyluke/xkcd-newtab",
  "chrome_url_overrides": {
    "newtab": "xkcd-newtab.html"
  },
  "permissions": [
    "*://xkcd.com/*",
    "webRequest"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{35ea65f2-503e-4f6d-bb3b-5765006d4620}"
    }
  }
}