PPWIZARD is a free preprocessor for HTML, REXX, Visual Basic or any text files.
This variable contains the level of file inclusion starting at 1. For each #include it goes up by one and goes back down by 1 when processing of that file completes.
This is a Standard Definition which always exists (you don't need to #define it). Note that you can create your own variations or completely new ones (see the examples).