The Replication Tool in Kafka is used for a high-level design to maintain Kafka replicas. Some of the replication tools available are

Preferred Replica Leader Election Tool: Partitions are distributed to multiple brokers in a cluster, each copy known as a replica. The preferred replica usually refers to the leader. The brokers distribute the leader role evenly across the cluster for various partitions. Still, an imbalance can occur over time due to failures, planned shutdowns, etc. in such cases, you can use the replication tool to maintain the load balancing by reassigning the preferred replicas and hence, the leaders.

Topics tool: Kafka topics tool is responsible for handling all management operations related to topics, which include

Listing and describing topics

Creating topics

Changing topics

Adding partitions to a topic

Deleting topics

Reassign partitions tool: This tool changes the replicas assigned to a partition. This means adding or removing followers associated with a partition.

StateChangeLogMerger tool: This tool is used to collect data from the brokers in a particular cluster, formats it into a central log, and help to troubleshoot issues with state changes. Often, problems may arise with the leader election for a particular partition. This tool can be used to determine what caused the problem.

Change topic configuration tool: used to Add new config options, Change existing config options, and Remove config options

https://hazelcast.com/blog/spring-boot-hazelcast-session-replication/