I ran cpan_grep.pl using the search /[*\@\$\%]DB::/, to find modules that interact with perl5db.pl. The results were... voluminous. But interesting too.

The vast majority of the references to the DB package were:

• using $DB::single = 1 to allow the module's author to start the Perl debugger, hit 'r'un, and for the debugger to automatically stop at that line
• accessing @DB::args — TODO: figure out what this means

TODO: continue processing the results