Examine source code of Eight Dollars for Firefox

{
  "manifest_version": 2,
  "name": "Eight Dollars for Firefox",
  "version": "1.1",
  "description": "Eight Dollars for Firefox can help you tell the difference between actual verified accounts and twitter blue users.",
  "icons": {
    "16": "./assets/16.png",
    "32": "./assets/32.png",
    "48": "./assets/48.png",
    "256": "./assets/256.png",
    "512": "./assets/512.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://twitter.com/*",
        "https://mobile.twitter.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{2c09f002-e563-4d08-bd31-ba0a93fd3a30}"
    }
  }
}