The User plugin is installed with the JFBConnect component itself, and is not a separate download. The same is true for the authentication and system plugins. We do this to make sure that these are always the correct versions to work properly with each other.
If you need to reinstall the plugins, you can find them in the /admin/packages directory of the main component zip file.
Hope this helps, and good luck!
can't find the user plugin to download
