The extension breaking changes made to the Firefox 3 toolbar IDs has been reverted and patched to get the same result in a different way. Any extensions that broke in a nightly version of Firefox 3 should be working correctly now. We also made sure to get the fix into Firefox 3 beta 3. Big “thank you” goes out to Dave, Dão and Gavin for helping me get the patch right and to Connor and Beltzner for making this a critical enough to get into Beta 3.
Scriptable IO is a new extension convenience library added to Firefox 3 (bug 380813). It has a lot of nice methods for doing IO without doing much XPCOM. Unfortunately, we found a problem which is related to Scriptable IO, but I haven’t figured out exactly how yet. To fix the problem, we had to backout Scriptable IO for now. We also had some other issues with the API that need to be worked through.
I know of at least one Firefox 3 compatible extension has been affected by this backout. The workarounds are to use the more verbose XPCOM versions of the features. Hopefully, we can take a look getting Scriptable IO back in the future.