Examine source code of Tab cycle Plus

{
  "manifest_version": 2,
  "name": "Tab cycle Plus",
  "version": "1.0.1",
  "description": "A simple tab cycle extension compatible with Firefox. It is an updated version of Tab Cycle.\n\nWhen enabled, this extension cycles through all the open tabs every x seconds (configurable).\n\nTo enable or disable the cycling a button is available under the Extensions button. Another setting is available to enable the extension automatically on browser startup.",
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-cycle-plus@example.com",
      "strict_min_version": "57.0"
    }
  },
  "icons": {
    "48": "icons/icon_48.png",
    "96": "icons/icon_96.png"
  },
  "permissions": [
    "tabs",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icons/cycle-disabled.png",
    "default_title": "Enable tab cycle"
  },
  "options_ui": {
    "page": "settings/settings.html",
    "browser_style": true
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  }
}