Examine source code of Insta Layout Remover

{
  "manifest_version": 2,
  "name": "instagram-images-layout-remover",
  "version": "0.0.1",
  "description": "Removes the layout from instagram images so you can save them by right clicking and saving as.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.instagram.com/*"
      ],
      "js": [
        "index.js"
      ]
    }
  ]
}