Examine source code of Focus Mode Toggle

{
  "manifest_version": 2,
  "name": "Focus Mode Toggle",
  "version": "1.0",
  "description": "Hide distractions like images and videos for focused reading.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Focus Mode Toggle",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b190f75b-64f0-4ba0-b95f-6dc51bb25c27}"
    }
  }
}