Examine source code of BookmarksToFile

{
  "description": "Addon to generate bookmarks as URL files. The interface allows you to select which bookmarks you want to extract and the result is delivered in a zip file",
  "manifest_version": 2,
  "name": "BookmarksToFile",
  "version": "3.0",
  "homepage_url": "https://github.com/Rebel1898",
  "browser_action": {
    "default_icon": "icons/bookmarkicon3.png",
    "default_title": "BookmarksToFile."
  },
  "background": {
    "scripts": [
      "background.js",
      "background2.js",
      "fflate.min.js"
    ]
  },
  "permissions": [
    "bookmarks",
    "tabs",
    "downloads"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4728b645-d874-43ce-93be-2b6c13ff4a2d}"
    }
  }
}