Sd_Basic_Trace_Flags

The Sd_Basic_Trace_Flags option (in the file sdbasic.cm) specifies how to format the security trace file (see Sd_Basic_Trace_File). If you specify prefix, the output prefix is included in the trace information. The prefix indicates the module from which the trace information originates. If you specify timestamp the trace information is timestamped.

You can specify either prefix or timestamp or both separated by a comma:

setopt sd_basic_trace_flags prefix, timestamp 

Unsetting the option using either unsetopt, or using setopt to change the value to unknown, clears all the flags.