Examine source code of Ptaszor Swapper

{
  "manifest_version": 2,
  "name": "Ptaszor Swapper",
  "version": "1.1",
  "description": "Changes all images to the image of wet owl",
  "icons": {
    "48": "icons/ptaszor-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "ptaszor.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{17da3e37-a328-4a81-b602-5ec6c52c1db7}"
    }
  }
}