I'm having a problem after installing an application that I remember having installed a system extension "Back in the Day".
Now when I boot I get the "Welcome to Mac OS" screen, then I get the bomb dialog which just says "unimplemented trap".
Can someone help give me some insight as to what may be going on and where I might be able to set breakpoints?
I'm running GitHub trunk, which I've built on VS 2017, so I have full debug capability.
EDIT: So, the mouse still works and I can click on the dialog box to reboot.

I wrote a doc on 68K A-trap https://github.com/cebix/macemu/wiki/ROM-Analysis-in-Basilisk-II-Emulation#mac-rom-in-real-macintosh-hardware. In a nutshell, it just invent 68K instruction in software manner. But I'm not sure what your system extension tries to do.

For break point, I sent a PR (https://github.com/cebix/macemu/commit/ ... 8d664ec6e3) that allow setting an emulation break point even starting in loading ROM. So it should fit your purpose to figure out your system extension at the start up.

Please note that the debugger of target platform compiled code (in your case VS debugger or GDB in Linux) is not useful at all for debugging 68K application in emulation. You must know 68K assembly and use BII emulator break point, instead.

In any case, it is difficult to debug Mac application written in 68K assembly. Good luck.

_________________
There is an App for that!
https://github.com/rickyzhang82

It's not my code that I'm trying to debug. I installed Codewarrior 10 Gold from one of the obsolete Macintosh software archives. I was wondering if there's something not implemented in Basilisk.

Could very well be. BasiliskII and SheepShaver are far from complete emulators.