Examine source code of Bookmark Express

{
  "browser_specific_settings": {
    "gecko": {
      "id": "aownchandia@example.com"
    }
  },
  "manifest_version": 3,
  "name": "Bookmark Express",
  "version": "1.0",
  "description": "Bookmark Express Uses the Firefox bookmarks API to search through, add and remove bookmarks from the user's bookmark tree.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icon.png"
  },
  "permissions": [
    "bookmarks"
  ]
}