@Override
    public boolean equals(Object o) {
        if (o == null || !(o.getClass().equals(QuorumFeatures.class))) return false;
        QuorumFeatures other = (QuorumFeatures) o;
        return nodeId == other.nodeId &&
            localSupportedFeatures.equals(other.localSupportedFeatures) &&
            quorumNodeIds.equals(other.quorumNodeIds);
    }
A holder class of the local node's supported feature flags as well as the quorum node IDs.
metadata/src/main/java/org/apache/kafka/controller/QuorumFeatures.java