when ICON is run in "atmosphere-mode" (i.e. when "model_type=1" in namelist "&master_model_nml"), the user defines his custom namelist-variables in a single file (whose path is given as variable "model_namelist_filename" in namelist "&master_model_nml"). This main-configuration file will be called "runtime user namelists file" or just "runtime namelists" in this page.
while running, ICON produces the file "nml.atmo.log", called "the log" below. The "log" states all namelists and all their variables, programmed in the binary. For each variable that the user has customized in his runtime namelists, with assigned value different than its default, the log records both the user-set value and its original default. For the rest of the variables (i.e those that the user hasn't override in his runtime namelists), only their default value is recorder at the log.
Notice that a namelist variable retains its default value during the model run, in two occasions: either because the user doesn't mention it in his runtime namelists, or because although mentioned, is assigned its default value. We call the first kind "implicit" defaults and the second "explicit" ones. The variables assigned in the runtime namelists with values other than their default, will be called "overridden".
By examining a "log", we can tell which variables are "overridden" (as the "log" records two values for them, the actual and the default). For the rest, if the runtime namelists file is also available, we can tell which are "explicitly" set (these mentioned in the runtime namelists) and which are "implicit" (all the rest, not found in the runtime namelists).
this application allows you to select available "logs" and see which variables are "overridden" in the user custom setup and which are not. If the corresponding runtime namelists file is also present, you can see which defaults are "explicit" or "implicit" (otherwise, all defaults appear as implicit). As more than one "logs" can be displayed, it can also act as a quick way to compare different user setups.