Examine source code of instagram-html5-controls

{
  "manifest_version": 2,
  "name": "instagram-html5-controls",
  "version": "1.0",
  "description": "Adds html5 controls to instagram on desktop",
  "content_scripts": [
    {
      "matches": [
        "*://*.instagram.com/*"
      ],
      "js": [
        "controls.js"
      ]
    }
  ]
}