I've gotten all the way through to the new debugger command API that Richard Foley added for 5.8.0. It makes a pretty decent POD document so far. Still a fair number of signposts for future investigation. I'm going to try to get the first version of it in for the 5.10/5.8.1 upcoming release.
This has taken way longer than I ever planned. Too much real code to write, and once you stop looking at the debugger code, it takes about 2 to 4 hours to get your brain back into that way of thinking.