This read-only OCTET STRING of 32 bytes, always all zeroes for the Packet Processing Engine and Turbo boards since a failure of either instead reboots the whole ES/1, contains information about the cause of a module's last unexpected self-reset since the ES/1 booted. An admin reads this after noticing an IOM module reset unexpectedly, to get diagnostic detail on why. For example, a non-zero hwFatalErr value on an IOM module that silently reset overnight gives the admin a specific fault code to investigate, whereas the same class of failure on the PPE or Turbo would instead have caused a full chassis reboot.