Examine source code of WebCull Bookmark Manager

{
  "name": "WebCull Bookmark Manager",
  "version": "5.0.5",
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "firefoxwebextension@webcull.com"
    }
  },
  "action": {
    "default_icon": {
      "16": "images/webcull-16x.png",
      "32": "images/webcull-32x.png",
      "48": "images/webcull-48x.png",
      "128": "images/webcull-128x.png"
    },
    "default_popup": "index.html",
    "default_title": "WebCull Bookmark Manager"
  },
  "permissions": [
    "tabs",
    "activeTab",
    "storage",
    "scripting",
    "alarms",
    "notifications"
  ],
  "background": {
    "scripts": [
      "init.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "commands": {
    "toggle-feature": {
      "suggested_key": {
        "default": "Alt+B",
        "linux": "Ctrl+B"
      },
      "description": "Open the bookmark manager in a new tab"
    }
  }
}