Examine source code of Focus Timer Simple

{
  "manifest_version": 2,
  "name": "Focus Timer Simple",
  "version": "1.0.0",
  "description": "A simple Pomodoro-style focus timer inside Firefox.",
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "focus-timer-simple@local-addon.example",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_title": "Focus Timer Simple",
    "default_popup": "popup.html"
  }
}