Examine source code of Twitter Enhancer

{
  "manifest_version": 2,
  "name": "Twitter Enhancer",
  "version": "1.1",
  "description": "This extension will help you to hide promoted tweets and promoted accounts from your timeline",
  "icons": {
    "32": "icons/tw-enhancer-32.png",
    "48": "icons/tw-enhancer-48.png",
    "64": "icons/tw-enhancer-64.png",
    "96": "icons/tw-enhancer-96.png",
    "128": "icons/tw-enhancer-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.twitter.com/*"
      ],
      "js": [
        "enhancer.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{19c0de62-3065-4e79-be7e-def98aa79f3c}"
    }
  }
}