Hi,
I believe it is a bridge as according to this page. I have installed the Atlas Hook for Kafka following the below instructions on HDP 3.1.0:
https://community.hortonworks.com/content/supportkb/246715/how-to-setup-apache-atlas-hook-for-apache...
If it is a bridge then we will need to run the script import-kafka.sh periodically to update Atlas as changes such as topic creation will not automatically flow through.
Thanks
Paul