2857
2858
2859
2860 - fold layer-20 changes into layer 19
2861 - test trace for comment tokens

Our first tiny case of a function tracing to multiple layers.
No idea if this is the most maintainable way to do this; we'll
see.
2862

Throw out earlier debug tracing. We'll return to that.
Perhaps it still makes sense to keep debug prints out
of the commit history.
But now we have the option to keep some around if they've
proven themselves.