Examine source code of TwinCone

{
  "manifest_version": 2,
  "name": "TwinCone",
  "description": "This extension automatically loads Basecone-scans and shows it within Twinfield.",
  "version": "2.5",
  "permissions": [],
  "icons": {
    "128": "icon128.png"
  },
  "web_accessible_resources": [
    "download.png"
  ],
  "background": {
    "scripts": [
      "jquery.js",
      "background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "https://c3.twinfield.com/*",
        "https://c4.twinfield.com/*",
        "https://c5.twinfield.com/*",
        "https://accounting.twinfield.com/*",
        "https://accounting2.twinfield.com/*"
      ],
      "all_frames": false,
      "js": [
        "jquery.js",
        "content.js"
      ],
      "css": [
        "style.css"
      ]
    }
  ]
}