More tinkering on the emulator for my 65C02 / TMS9918A homebrew build has resulting in many improvements to the debugger, including being able to step through the source assembly code, set and clear breakpoints,  break on interrupts, examine variables and constants, RAM and VRAM, click to labels, etc.

You can try it online here: https://visrealm.github.io/hbc-56/emulator/wasm/?rom=breakout