Examine source code of Simple Notepad

{
  "manifest_version": 2,
  "name": "Simple Notepad",
  "version": "1.0",
  "description": "A simple notepad, elegant and intuitive, for taking notes. Saves your notes when you close your browser.",
  "icons": {
    "16": "images/notepad-16.png",
    "32": "images/notepad-32.png",
    "64": "images/notepad-64.png",
    "128": "images/notepad-128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "js/dark-page.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_title": "Simple Notepad",
    "default_popup": "popup.html",
    "browser_style": true,
    "default_icon": {
      "64": "icons/icon.png"
    }
  },
  "web_accessible_resources": [
    "js/dark-page.js"
  ],
  "permissions": [
    "<all_urls>",
    "tabs",
    "storage"
  ]
}