Bug 617539 merged nsIDOMWindowUtils_MOZILLA_2_0_BRANCH back into the main interface:
However, there is one (presumably unused) consumer remaining:
This is a very simple change that would allow a new contributor to get used to our patch and review process.
Created attachment 546930 [details] [diff] [review]
Removes the function windowsUtils20 and so nsIDOMWindowUtils_MOZILLA_2_0_BRANCH