> indistinguishable from jdb. You can run ok(window) or whatever!

Almost, but more restricted.
In jdb you can type e2 and switch to another session and do other things, like look at the code you're working on,
or change db levels or shell escape or a few other things; not here.
It's just js expressions only.
So if you want to read the code around your breakpoint you have to do it from another console / window.
I wanted to do all those other things here but it's just too hard for tecnical reasons.
In the breakpoint, js is actually running.
In jdb it is not.
Thus bp is more restricted and to remind you of that, you get the bp: prompt.

You have to  place your breakpoints then recompile so to speak, or actually, rebrowse, so it's not as cool as real breakpoints,
but you know, it's better than nothing.
I use to stick code in to copy local variables up to global so I could look at them after the fact, guessing which variables I might want to see, etc, that was pretty awkward.

I also mentioned in my comments that while in this breakpoint you can change local variables, then . to exit and duktape continues
with the modified variables; but not sure you should really do that.

Karl Dahlke