The reason given was: Removed in favor of the official OpenStack modules
Add this module to a Bolt project:
bolt module add puppetlabs-horizon
Add this declaration to your Puppetfile:
mod 'puppetlabs-horizon', '4.1.0'
Manually install this module with Puppet module tool:
puppet module install puppetlabs-horizon --version 4.1.0
Downloading to your local machine is not typically how you would use a Puppet module to manage your infrastructure, but you may want to download the module in order to inspect the code or for testing purposes.