Mozilla maintains blocklist of add-ons (extensions, themes, plugins) which causes crashes, performance and security issues for Firefox, if you don’t know Firefox automatically sends crash reports to Mozilla when Firefox crashes with the details page you’re on, this information will help Mozilla to make Firefox more stable and secure in future versions by fixing those bugs.
Third-party add-ons always a concern and issue for Mozilla
Mozilla always worries about third-party add-ons installed in users Computers which causes severe crashes and performance issues for Firefox, hence Mozilla decided to disable all third party add-ons by default in upcoming Firefox 8.
Mozilla considers following reasons for blocking an add-on
- Critical Security vulnerabilities
- High crash volume (e.g. 10,000 or more in a week)
- Malicious in nature
- Severe performance impact
- Severe bugs that unintentionally effect core Firefox features
Types of Blocked add-ons
Mozilla categories blocked add-ons into two: one soft-block where the add-on will be automatically blocked and notified the user about the same and allows users to re-enable the add-on at any time whenever he wants.
Hard-block is the second one is more the case with malicious add-ons where add-on once detected will be permanently blocked/disabled and doesn’t allows user to enable or overwrite the block.
Mozilla does contacts vendors before blocking the add-ons and gives them 3 calendar days to release the fix version.
You can find currently blocked add-ons here.