0) Debug folder used to hold a debugging library of o2grammars used by programs: o2 and o2linker
1) U can turn on dynamic tracing facilities of Yacco2 or add your own tracing stuff within these grammars
2) Regen the grammars using o2grammars.sh
3) Rebuild the debug  o2grammars library using bld_bash_APPLE or other platform scripts.
   Make sure you put this debug version in this folder
4) Then rebuild o2 and / or o2linker and link them against this debug library

Please read the bld_bash* scripts where there are appropriate debug comments.

If u suspect Yacco2's grammars are in trouble, then put in your own tracing facilities and rebuild them.
Have a read of compiler/grammars/makefile_APPLE script or other platforms 

Please read o2book.pdf for more comments on tracing facilities.