The value of a configuration variable is the value of the setting in question at the time the macro is executed. If the original setting in your configuration file was overridden by a configuration-variable assignment in a marker or another macro, the override, not the original value, is the value returned for <$$[section]key>. See §31.2 .
If you use a configuration variable to retrieve the value of a setting when the key is not present in your configuration file, or the section itself is missing from your configuration file, the value of <$$[section]key> is the default value specified for that key in one of the following references:
If you use a configuration variable to retrieve a value when <$$[section]key> refers to an invalid configuration-file section, or to an invalid key, Mif2Go returns 0 (zero), which is interpreted as false in a conditional expression <$_if($$[section]key ...)>; see §188.8.131.52 .
> 27 Working with Mif2Go macros > 27.4 Capturing settings with configuration variables