dbs/db2/cli_trace is a SAP Parameter attribute which is used to control DB2: switch on/off CLI trace information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
Parameter can be used to switch on/off the trace for the call level
interface ( CLI ). Value 0 means off, value 1 means on. The trace is
written in the DIR_HOME directory by default. If you want to change the
directory you can use the profile parameter cli_trace_dir.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.