As you're aware, Rene Gollent (the yak man) has been working away on improving Haiku's debugger, an essential tool for developers. ICO has written about it in the past, at last year's BeGeistert. Rene recently wrote a post over at Haiku's site detailing some of the new features he introduced to the app.
Some of them are Return Values, Improved Typecasts and Array Ranges, among others. It's a long post and, I confess, too technical for me, but judging from the reactions I've seen all over the place, it's not only impressive work, it'll prove very helpful to developers working on Haiku/3rd party applications. Nice!