Markus Stange did a pretty awesome thing for those of us who work with the Mozilla trees and tinderboxen:
First of all, bookmark that action.
As for how it works, a couple minutes of playing around should explain it. Basically it’s a running changelog with associated builds and status, plus an at-a-glance view of the tree in the bottom right, and details of a selected run in the bottom left.
If it were covered in shaved black truffle and a velvety 25 year old balsamic, it would be only marginally more delicious.
If you see mstange on IRC, give him your love. If you have suggestions, give him your patches.
[Update: Why yes, it does require querySelectorAll support. I trust you have a browser that does that, right?]