According to https://github.com/MariaDB/mariadb-connector-j/blob/master/src/main/java/org/mariadb/jdbc/MariaDbDatabaseMetaData.java , when querying for database Metadata in getExportedKeys(), getImportedKeys() and getCrossReference(), the driver always returns the constant value 6 (=importedKeyInitiallyImmediate). This implies that the constraint can actually be set into a deferred state (=checking at the end of the transaction, NOT disabling constraint checking altogether). AFAIK deferred constraints is a capability that MariaDB does not currently implements. This creates confusion in my application (and, consequently, an SQL syntax error when trying to put the constraint in a deferred state).
Please change this value to the (IMHO) correct value of 7 (importedKeyNotDeferrable) so applications who rely on this information can behave correctly.