Examine source code of Quick Reading Mode

{
  "manifest_version": 2,
  "name": "Quick Reading Mode",
  "version": "1.0",
  "description": "Toggle a distraction-free reading mode on any webpage.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icons/read-mode-48.png",
    "default_popup": "popup.html",
    "default_title": "Reading Mode"
  },
  "icons": {
    "48": "icons/read-mode-48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{af425e62-7a88-4048-b241-2f3c7ed0476a}"
    }
  }
}