Examine source code of iframe Resizer

{
  "name": "iframe Resizer",
  "description": "Easily control the size of an iframe",
  "version": "1.0.1",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "./icons/iframe-resizer-16.png",
      "32": "./icons/iframe-resizer-32.png",
      "48": "./icons/iframe-resizer-48.png",
      "128": "./icons/iframe-resizer-128.png"
    }
  },
  "icons": {
    "16": "./icons/iframe-resizer-16.png",
    "32": "./icons/iframe-resizer-32.png",
    "48": "./icons/iframe-resizer-48.png",
    "128": "./icons/iframe-resizer-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{5dd48ba6-8b7c-4d8a-be91-58e806ee9cad}"
    }
  }
}