Examine source code of Twitter Draft

{
  "manifest_version": 2,
  "name": "Twitter Draft",
  "short_name": "twd",
  "version": "1.0.2resigned1",
  "description": "A simple extension to store your tweets as draft",
  "icons": {
    "48": "icons/logo-48.png",
    "96": "icons/logo-96.png",
    "128": "icons/logo-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/"
      ],
      "js": [
        "index.js"
      ]
    }
  ],
  "homepage_url": "https://github.com/msudgh/twitter-draft",
  "browser_specific_settings": {
    "gecko": {
      "id": "{216dccc1-2527-4210-b310-9fa9e727c302}"
    }
  }
}