This is a free-text, human-readable message describing the last non-fatal error, meant to be read directly rather than decoded from a numeric table. This is the field an admin actually pastes into a trouble ticket, since it typically spells out in plain terms what the major and minor error codes only encode numerically. For example, cardDiagNonFatalStr might read DRAM parity error bank 3, giving the technician an immediately actionable description without needing the vendor's code lookup table.