Examine source code of BookmarkCycler

{
  "manifest_version": 2,
  "name": "BookmarkCycler",
  "version": "1.2.1",
  "description": "Automatically load next Bookmark from selected Bookmark Folder(s)",
  "applications": {
    "gecko": {
      "id": "bookmarkcycler@software.donnapaul.net",
      "strict_min_version": "57.0a1"
    }
  },
  "homepage_url": "http://software.donnapaul.net/bookmarkcycler.html",
  "developer": {
    "name": "PaulJayD",
    "url": "https://addons.mozilla.org/en-US/firefox/addon/bookmarkcycler/"
  },
  "default_locale": "en_US",
  "permissions": [
    "<all_urls>",
    "activeTab",
    "bookmarks",
    "storage",
    "tabs"
  ],
  "browser_action": {
    "default_title": "Bookmark Cycler",
    "default_popup": "bookmark.html",
    "default_icon": "icons/bookmarkcycler.ico",
    "browser_style": false
  },
  "icons": {
    "48": "icons/bookmarkcycler.ico"
  }
}