Examine source code of Scribble Pad

{
  "manifest_version": 2,
  "name": "Scribble Pad",
  "version": "3.0.3",
  "description": "Scribble Pad turns any website into your personal canvas. Draw, sketch, write notes, capture screenshots and annotate in real time.",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "browser_action": {
    "default_title": "Scribble Pad",
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png",
      "48": "icons/icon-48.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "permissions": [
    "activeTab",
    "storage",
    "file://*/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content-script.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    "fonts/ArchitectsDaughter-Regular.woff2"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{b649228b-ccba-46d2-897c-6903b1b4123e}"
    }
  }
}