Examine source code of Limit Twitter

{
  "manifest_version": 2,
  "name": "Limit Twitter",
  "version": "0.2.1",
  "default_locale": "en",
  "description": "__MSG_extensionDescription__",
  "icons": {
    "48": "icons/limittwittericon-48.png"
  },
  "author": "Kunisaki Saikoh",
  "developer": {
    "name": "Kunisaki Saikoh",
    "url": "https://capybara-wonder.com/"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.twitter.com/*"
      ],
      "js": [
        "limit_twitter.js"
      ],
      "run_at": "document_start"
    }
  ],
  "options_ui": {
    "page": "options.html"
  },
  "permissions": [
    "storage"
  ]
}