Examine source code of shipit

{
  "name": "shipit",
  "manifest_version": 2,
  "version": "0.1.4",
  "permissions": [
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "./browser-polyfill.min.js",
        "./content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    "shipit.js"
  ]
}