Question about LibrdKafkaError Interface

Hi all - just upgrading noderdkafka from a rather old version, and noticed -

Looking at:
lib/error.js and

export interface LibrdKafkaError {
message: string;
code: number;
errno: number;
origin: string;
stack?: string;
isFatal?: boolean;
isRetriable?: boolean;
isTxnRequiresAbort?: boolean;
}

Why do we need to have both code and errno? Is this some sort of legacy compatibility?

Thanks

Start by reading lib/error.js and the LibrdKafkaError interface, then trace the issue's referenced error fields through the surrounding binding code. Done means establishing and documenting why both code and errno exist, or identifying a clearly agreed API change; the issue currently names no tests or other entry points.

Written by the indexing model from the issue text.