
Developers though have it better, Firefox 10 brings a number of changes that should improve the existing dev tools but also comes with a few new tools as well.
Add-ons compatible by default
The big new feature in Firefox 10, at least in terms of impact, is default add-on compatibility. All add-ons that are listed as supporting Firefox 4 or greater will be allowed to work and be installed in Firefox 10.
Some of them may need to be updated and may still be incompatible, but this is judged on a case-by-case basis, unless they are proven not to work, add-ons will be marked as compatible.
This should mean that people will find it easier to update to a new Firefox version and won't be stuck with old, unsafe and unsupported versions simply because their favorite add-ons don't work."
'via Blog this'