Examine source code of Instagram Unlock

{
  "manifest_version": 2,
  "name": "Instagram Unlock",
  "version": "0.8.1",
  "description": "Browse Instagram pages without logging in!",
  "icons": {
    "48": "icons/Instaunlock-48.png",
    "96": "icons/Instaunlock-96.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.instagram.com/*"
      ],
      "js": [
        "instaunlock.js"
      ]
    }
  ]
}