Examine source code of Todoist Quick Add

{
  "manifest_version": 3,
  "name": "Todoist Quick Add",
  "version": "1.1",
  "description": "Quickly add a task to Todoist with the current page's title and URL.",
  "icons": {
    "16": "icon-16.png",
    "32": "icon-32.png",
    "48": "icon-48.png",
    "128": "icon-128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon-16.png",
      "32": "icon-32.png",
      "48": "icon-48.png",
      "128": "icon-128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "todoist-quick-add@viktor.local"
    }
  }
}