Examine source code of Page Block

{
  "manifest_version": 2,
  "name": "Page Block",
  "version": "1.3.0",
  "author": "Leon de Klerk",
  "description": "A simple extension that allows you to set a list of websites which you can only visit x times in an interval. You can chose a hourly, daily or weekly interval, when the limit is reached within that interval the tab will automatically close. As long as you are on a page, refreshing will not count towards the limit, but opening a new tab will.",
  "homepage_url": "https://github.com/leondeklerk/page-block",
  "icons": {
    "48": "/logo-48.png",
    "96": "/logo-96.png"
  },
  "permissions": [
    "activeTab",
    "storage",
    "tabs"
  ],
  "browser_action": {
    "default_icon": "/logo.png",
    "default_title": "Page Block",
    "default_popup": "/index.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": true,
    "type": "module"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4fab38e9-c167-4dee-b27b-81ffeee5e7d6}"
    },
    "gecko-android": {
      "strict_min_version": "120"
    }
  }
}