https://github.com/rcorsi/CoCo-xroar-variable-profiler
It uses GDB connected to XRoar to profile BASIC variable use (to let you know which ones are worth DIMming at the head of your program). The breakpoint addresses are CoCo-specific, but could doubtless be easily translated to Dragon BASIC.
But the reason I'm linking it is it demonstrates some quite fancy GDB-fu. The breakpoints are given sets of commands to run using a language built into GDB that I didn't even know it had
It even has some optional calling out to Python scripting. Could be a useful little primer on such things and enable some next-level debugging.