Unknown error 188

I have a query that very sporadically returns with 'Unknown error 188'.

This could well be caused by a time limit set with SET max_statement_time statement, but I'm not sure.

In the mariadb source code I found these define statements:
#define HA_ERR_ABORTED_BY_USER 188
and
#define HA_ERR_QUERY_INTERRUPTED HA_ERR_ABORTED_BY_USER

The documentation for max_statement_time does not state any error codes that could be interpreted as a query that is aborted due to a time limit. So far I've found that
error 1028 - Sort aborted and 1969 - Query execution was interrupted (max_statement_time exceeded) can happen.

Should I add 188 to this list in my application? Or is this a bug and should error 1969 be returned instead of 188?