The errors that are reported when the client-side max_allowed_packet limit is reached are not helpful and at worst are misleading: exceeding the value in a resultset causes the error to be reported as:

ERROR 2013 (HY000): Lost connection to server during query

The error is technically true: the connection is lost but it was lost because the connector itself closed it because the client-side limit for max_allowed_packet was exceeded. This makes it hard to debug problems related resultsets when the true cause of the error is not known.

At the time of writing, the default values for the option are also not documented but based on the source code, it appears to be 1GiB. This also differs from the MariaDB default of 16MiB and the default that is used by the mariadb client, also 16MiB.