Examine source code of Web Notification Logger

{
  "manifest_version": 2,
  "name": "Notification Logger",
  "version": "1.0.0",
  "description": "Logs web notifications and displays them in a popup.",
  "permissions": [
    "notifications",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": "icon/96.png"
  },
  "icons": {
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2751f089-5158-4be8-ba47-54a99937a58a}"
    }
  }
}