Examine source code of gitphy

{
  "name": "gitphy",
  "version": "1.1.1",
  "manifest_version": 2,
  "description": "Put gifs in your Github issues and pull requests without leaving the textarea",
  "author": "Kevin Wu",
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://github.com/*"
      ],
      "css": [
        "index.css"
      ],
      "js": [
        "index.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "https://github.com/*",
    "https://*.giphy.com/*"
  ],
  "web_accessible_resources": [
    "giphy-attribution.png"
  ]
}