Examine source code of ZoomyCircle

{
  "manifest_version": 2,
  "name": "ZoomyCircle",
  "version": "1.0",
  "description": "Zoom into images using a circular magnifying glass on hover.",
  "permissions": [
    "activeTab"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "style.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{24f411e1-3f22-4bec-b685-fbda28f629d4}"
    }
  }
}