The DBGLVL option gives you control over the output level of the model debugging command, DEBUG.  The debugger is very useful in tracking down problems in models that are either infeasible or unbounded.  Possible output levels range from 1 (minimum output) to 15 (maximum output).  In general, you will want to generate as much output as possible.  The only reason to restrict the amount of output would be to speed debugging times on large models.

The default setting for the debugger output level is 15.