This YOURLS plugin enhances the functionality of the default URL shortener by allowing the creation of multiple unique short URLs that redirect to the same destination. Unlike the standard 'Allow Existing URLs' plugin, this tool completely bypasses the uniqueness check when requested, providing true duplicate functionality. This is achieved by hooking into the `url_exists` and `shunt_add_new_link` filters, while also maintaining the original 'Allow Existing URLs' behavior as a fallback.