The break on modifications should already be possible, by adding breakpoints to Mutation Events (as you can do already with e.g. mouse related events).

However, Mutation Events were marked as deprecated by allegedly bad design. We should be using MutationObserver[1] instead (which, I believe, will be equally helpful in observing changes).

[1] https://developer.mozilla.org/en-US/docs/Web/API/MutationObs...