I'm thinking it could make sense to tin a small strand of wire to make a fine probe, and see if I can detect activity on any of the chip's pins when the programmer probes it, using my cheap pocket oscilloscope.

Doing that, I expect to find a way to use my oscilloscope to make a log of logic behavior on a pin. Maybe I could then log the logic behavior of all the pins.

I glanced at the source code, and it looks like it uses bitbanging to set each clock tick, without regard to a constant time base or anything.

I could glance a little further to see what kind of activity is expected on each pin.

I could also attach leds to see the activity, if I have any.