Examine source code of Font Identifiers

{
  "manifest_version": 2,
  "name": "Font Identifier",
  "version": "1.0",
  "description": "Identify fonts used on a webpage.",
  "icons": {
    "48": "icon.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6fde90e8-1fc8-467a-9f6d-a32a80d496c3}"
    }
  }
}