[fcavallarin]

Good point - in theory a full time-travel debugger is more powerful. The practical limitation is that time-travel for JavaScript usually requires instrumenting the code or running inside a custom record/replay environment. Today, JavaScript doesn’t expose any record/replay mechanism, access to hardware breakpoints, or the internal VM state needed to run execution backwards.

The browser’s debugging API (CDP) also doesn’t provide a way to capture or rewind engine state without modifying the application.

BDHS works within the constraints of zero instrumentation: it relies only on Debugger.paused and heap snapshots, so it can trace where a value originates without altering the code being debugged.