Debug is a reserved word used to tell Bennu to go into debug mode, only if the DCB was compiled with debug information (compiler option
-g). If the module mod_debug was imported as well, the console is immediately invoked and one can begin tracing from the debug statement.
Here's a handy page about debugging a Bennu program.
Function int debug_warning(string warning) Begin say("Warning: " + warning); debug; return 0; End