Ahh, core dump, not "core" file. Ok, slightly ambiguous and I feel sheepish about it.
I've also looked at core files in GDB, not directly. They're about as unintelligible as a core dump from a C program. It all depends on -fno-omit-frame-pointer: with it, it's usable. Without it, good luck because it involves un-convoluting the optimizer. That's both for C and C++.
> I have 20+ years of experience writing C++.
> Yes, I've looked at "core" C++ headers and source.
https://en.wikipedia.org/wiki/Core_dump