Examine source code of Focus 15

{
  "manifest_version": 3,
  "name": "Focus 15",
  "version": "1.0.0",
  "description": "Block distracting sites after 15 minutes per day.",
  "browser_specific_settings": {
    "gecko": {
      "id": "focus15@example.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage",
    "tabs",
    "alarms"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "Focus 15",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "web_accessible_resources": [
    {
      "resources": [
        "blocked.html"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}