Kx has much improved Q/k's debugging capabilities - including stack traces.

see: https://code.kx.com/q/basics/debug/

backtrace has been supported for some time. the debug facilities are nice

https://code.kx.com/q/basics/debug/#stack-frames

Oh absolutely. Pg talks at some point about how LISP macros can create a sense of godlike power / mania, and I think there's some of that in APL-land too. The true titans don't need to debug in the traditional sense - a whole program fits on a single screen, they can load it in their head, reason about it, and see what happened.

Non-titanic engineers accidentally generate bugs in these languages with high "floor" IQ requirements, and debugging someone else's K code is terrible. Debugging your own K code is terrible, not less because when you get help you will feel very, very stupid indeed :)