Examine source code of AshiMashi

{
  "manifest_version": 2,
  "name": "AshiMashi",
  "version": "0.1.0",
  "description": "A less time consuming version of Twitter. By now it removes replies and trending box",
  "content_scripts": [
    {
      "matches": [
        "*://*.twitter.com/*"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "icons": {
    "48": "images/logo.png"
  }
}