Examine source code of Zen Break Overlay

{
  "manifest_version": 3,
  "name": "Zen Break Overlay",
  "version": "0.1.0",
  "description": "Every 30 minutes, show a stylish 5-minute break overlay in Zen/Firefox.",
  "permissions": [
    "storage",
    "scripting",
    "tabs",
    "alarms",
    "notifications"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "Zen Break Overlay",
    "default_popup": "popup.html",
    "default_icon": "icons/work.png"
  },
  "icons": {
    "48": "icons/work.png",
    "96": "icons/work.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "zen-break@example.local",
      "strict_min_version": "121.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}